I don't think anybody would be remotely close to be willing to port a game onto the Saturn. The Saturn is suppose to be impossible to program for, one of the reasons it failed.
The DC is strong enough to run emulators for older consoles, yes, but don't expect to ever see any emulators for the Saturn. I would be shocked to find out some one was coding/porting an emulator for the Saturn. It just wont happen. Not just because it's hard to program for, but also because it's weaker than the DC.
But what you said about Sonic Jam, Wiki says...
The games were not simply direct emulations like in later compilations, but rather elaborate ports to utilize the Saturn hardware.
So apparently Sega ported the games onto the Saturn, so I guess this is why there's some minor visual and audible differences.
edit: I just realized you're talking about three completely different things lol. The title of the thread says backwards compatibility while the thread mentions porting and emulating games. They are three very different things, so I'm not sure what exactly you're asking now.
You say your Genesis can play SMS games (backwards compatibility) obviously via an adapter. Are you asking if an adapter could be made to play Genesis games on the Saturn? Then you talk about Sonic Jams, which the included games were (apparently) actually ported to the Saturn. And then you talk about emulators on consoles, which is something else entirely.
Did you mean to talk about three different ideas?... I'm just confused what you meant.