My vacuum formed cases are slightly too small for this project, so got these - 2L lunch boxes, 22 x 15 cms.
This is not a naff idea, it is actually a very good one.
The base to lunchboxes/tupperware is not very strong, but that doesn't matter, the base will be replaced with 2mm perspex. The sides are angled and so are the edges, which is nice. Not going to keep all the slope, but enough. The sides are strong and smooth.
My case, (before sanding) vs the lunchbox. I will show that you can make a very nice looking case with tupperware boxes!

The top and the bottom of the lunchboxes will be removed, to eliminate the lid area and also the bottom of the lunchbox is too flexible and mis-shaped - so replacing the base with 2mm perspex.
Mark out some of the base to remove by running a medium thick CD marker pen down the base, then cutting out the area.

Then mark out the inside shape of the lunchbox with a CD marker pen onto the perspex, and cut out, using a circular cutter on the dremel, and finishing off with a sanding drum

Use hot glue to seal the perspex to the lunchbox along the whole inside, taking care to keep the perspex flat and the lunchbox snug against it. I know people say hot glue isn't strong and can flex, etc - but actually doesn't with these types of material.

To prove the portable is still small:

Then, use an electric sander to smooth the surface and edges together. The result is a very smooth surface, that can be sanded with a foam sanding block later to finish off.

It will be sanded down better later, when the button holes are in, etc; however, this ensures I can measure the sides to trim down evenly.
There will be two lunchboxes prepared, one for top and one for bottom of case.
You notice, I have retained the slope on the top of the lunchbox, so it is curved and not flat, the sides are slightly sloping too - nice!
This will look awesome when done. A fair bit of work to do on this yet though to get to that stage!!
Had brainwave - for the CD tray - why make a clip on drive unit, like on the IntoPlay (case slightly too small to incorporate a PSone front) - the tupperware is pretty near exactly the same breadth as the PSone console, slightly wider. PERFECT! I can modify the PSone case top to take a DreamCast drive unit, and thereby be able to use a pre-made CD loader surround! Needs modding work, but result is worth it - also, the backing to the case will be nicely rounded in shape!

Drew out an outline of a CD on the DreamCast. Can't use a DC case - far too big.

Used a drill to cut out the hole, afterwards, used a sanding drum to finish off.

result

Did same on PSone case front:

Trimmed the DC drive a bit to fit like this



You can see how much I have had to trim off the DC drive surround - right up near the motor gears, in fact. Cut it quite exact, so will need to use this "backup" drive as the main drive now! (not too hard to connect the ribbon).

Had to cut more off the PSone case, so the drive unit can sink properly in, and the CD's can spin freely (they didn't when I started this trimming). Great now.

As you see with this design, I need the plastic case surround for the DC, or the motor assembly won't be positioned properly. Another reason I can't reduce this part further in height. After this pic was taken, removed the surplus legs on the case.

Removed the lid from the PSone case, drew a cut-out and stuck it onto the case in position, so the hinge mechanism is at the back of the case. Doing a template this way is efficient - just cut around the hole!

Used electric sander to sand down the top of the PSone case (another reason to remove the CD lid). This means it can be mounted better.

Putting the PSone case on top and bondo it would look amateurish and it would be hard to get the curves good, so much better to have the case back flat with a pop-up lid.
Cut out the CD tray from the case backing:

Lid lifts on the back of the case, there is a hole cut to take a button to press down onto the eject button. Overall, the assembly isn't much different to doing it any other way in regards to end thickness, however of course it looks far better.
Need to do some bondo and polyfiller filling just around the CD tray perimeter, and the finger cutout to remove CD's easily from the unit.

Made screwposts from old PSone controllers to keep the DC drive in place - 2 screw holes to keep the drive assembly secure and in the right place.

Swapped the old drive for a different one; circuit on the back of the laser assembly was a different colour, didn't think it mattered, obviously it did as the DC didn't play any games. Swapped it back to the old one again (after making the cutout in the drive top as per the other one, so it fitted in the PSone assembly in the case), all fine.
Removed the metal plate under the drive unit. Cut away some of the plastic base too, so the power plugs fit through.
This keeps it all as low as possible.
Have to make sure the drive unit is straight with the ribbon to the bottom board, otherwise a game doesn't start as the ribbon isn't free enough to move. When I am confident it is positioned correctly (pretty sure at the moment), will hot glue it in place.
Idea is to release the top of the case from the system, unscrew 2 screws.
Looks like I have got the overall height so far to about 48mm; so estimate the final height of the portable will be 48mm + 6mm for the extra height to the back of the case, plus the PSone screen, case, controller about 18mm; so finish about 72mm; as previously estimated.
It is hard to see how a DreamCast can be made slimmer.

Implementing a feature into this - playing Q*Bert on the portable is too hard as you normally have to rotate your controller (can't do that if integrated into a portable), so going to use the screen and volume buttons as dual function as a "tilted" d-pad for Q*Bert. Just need a couple of switches to do this.
In the pic, the VMU will be on the top right, top left is an N64 SuperPad joystick (far more control than a normal joystick), d-pad on middle left side, speakers bottom left and right, start button (the diamond shaped button from a DC controller pad. More holes to make, yet. Everything had to be mapped out properly do didn't get into problems during assembly.

When done, will give the case top a good sanding and smoothing before spray painting.
I draw out the shapes using CD marker pens, use a slim drill bit to cut out near to the edges, then use sanding drums / grinding drums to finish the job (buttons) and / or sanding blocks / small files for straight pieces. Takes quite a while to do - a good few hours just to do what I did on the last pic!
Spent quite a while working out if to put the shoulder buttons under the case, to the sides, where. Decided on the top corners, just down from the top. Feels comfortable there.
Desoldered the variable pot from both of the shoulder buttons, hot glued them back in place. Cut holes in case, the trigger sticks out plenty, but not overly obviously.


After adding PolyFiller (fine crack, quick dry) on the rim to make it smooth with the top of the case (and not look like a lunchbox), gave it a thorough sanding with a foam sanding block.

PolyFiller is a good filler however of course it isn't strong in itself. You can add PVA to it afterwards to make it strong, however I have a better trick up my sleeve this time around - normally, you might have small pits or whatever in the case around where applied filler, etc. You then need to add a little more filler, sand etc. My idea is this - as you are using paint (spray paint) anyway, why not apply wall paint (matt) directly, then once dried, sand that smooth! Paint sands ok, smooth, and fills in tiny cracks etc too.

So, will sand that when dry; cut off about half the height of the lunchbox, sand smooth, then time to paint. The lunchbox is slightly curved, so if cut in nearly half height, to match the bottom half, then the two halves will meet quite exactly. The sides need reinforcement of course, will use perspex for that. I will also incorporate screw posts too.
On the top half of the case, there will be holes for the screen controls, system on/off and two 2P2T switches to alternate between the PSone screen controls and the slanted d-pad (Q*Bert).
BTW - People say Unreal Tournament isn't great, sure, however it was revamped for the DreamCast and looks pretty fine:
http://www.youtube.com/watch?v=5xjoxmB7cuw If it is as good as it looks, then that game and Quake 3 will be the main reasons for play on the portable for sure!
Here's the item before sanding, the height trimmed to 37mm high, as the final height of the system will be around 72-76mm, so this represents half the total height of the system.

After a coat of plastic primer spray paint and then couple of good coats of spray paint. Resting the case on a couple of old foam sanding blocks so the bottom doesn't stick to the box painting onto:

Need to sand it, may then just need a final coat, then varnishing. Once done, the holes will be checked and sanded if needed; then decals, then fill the case top with the electronics! The case base will need more work done yet.
This is going to look awesome when done! Remember a while back I said it might be based on a lunchbox but will look awesome??
Finished painting case top, given it a couple of coats of varnish. Also, painted the d-pad, joystick and contrast/volume buttons black.

The d-pad and action buttons I am using, and the surround for the action buttons, is from this generic PS1 controller. The d-pad is nice and deep, the buttons are flat.

Thought about using the official Dreamcast ones, but as you see, although the button tops are flat, the buttons are different heights!

These are the ones from the PS1 unofficial controller:

Tried to cut off the tops off the buttons on the MadCatz controller, but the buttons have a rubber surround, so didn't work, so trimmed off the top of the official Dreamcast controller action buttons, and sanded down to flat.

PolyWeld is a glue that welds and melts the plastic a bit so you get a weld joint rather than a glue joint. Problem is it doesn't work on many plastics, despite what it claims; when it works it works great though, fortunately it works on these two plastic types.
In pic, the first of the 4 buttons are in place. The Dreamcast buttons are about 1mm larger in diameter than the buttons using, so a little sanding does the trick!

The benefit of doing this work is that each button has a colour and letter on it, for during gameplay, so this method maintains that.
Secured the VMU unit in place, a bit of hot glue here and a bit there - the rubber coated contacts on the screen are extremely sensitive to making contact with the contacts on the board, it was a job to get them touching, but not too much, otherwise they flex and don't make contact.
Bent the VMU board back on itself, secured in place with a wire (the insulation part!). Electrical tape to stop shorts.
Button pad - tried using the original one from the controller, however, it was fussy about being in exactly the right place, and when it was, there wasn't much contact - didn't register much on my multimeter. This means in games, there is every likelyhood the controller won't know you pressed a button sometimes, which is a waste of time. Tried then to use the rubber topped tact switches and put them on perf board - couldn't get contact with the buttons exactly enough, so on third attempt, just hot glued each button to the hole directly - works fine!
Two pics for your viewing:

In this pic, you can see one of the speakers, the folded-back VMU and the button pad; lots more to do here yet.

Using the controller case, as did, means the buttons retain their orientation (slots in the back); I just glued the rubber tact switches to the top of the holder - pic below is from a spare, similar style controller.

Hot glue is strong; maybe its the branded stuff I use, don't know. Easy enough to cut perspex strips, put on top, glue down elsewhere, for extra strength, although hot glue by itself seems strong enough for the job.
Ok, made and installed the d-pad cross.

You can see how it was made by visiting my Wordpress site - link in the News section there...

(see my sig).
taking shape...
Video of WIP so far