New versions of Alien Breed 3d II: The Killing Grounds are totally playable on a 030 now too, so give that a go.
Also the ACA1230/56 does have a MMU so Shapeshifter will be no problem. It's the ACA1230/28 that misses out on the MMU, but neither of them have a FPU.
NetBSD would probably be better than Debian on the 030 so you might want to try that as well.
AmiMasterGear is the best emulator that you should definitely try, all those Sega Master System and Game Gear games should run full speed.
Get yourself a cheap PCMCIA ethernet or wireless card to come online and play Dynamite against us.
