I think it's best to realize that given bus speed limitations and CPU clock issues that an Amiga with 68k (even a souped up one) can't push textured polys around at any acceptable resolution.
Now with that said, yeah, you can get some screaming speeds out of UAE+Quake, or Doom on 68k based systems.
But Quake is after the Amiga's time, and "getting it to play" at tiny, tiny screensizes and tiny resolutions is an iffy prospect at best, assuming you want consistent FPS in double digits.
