Not sure about the Amiga, I've tried 2 MC68HC000P16's in an ST and because its CMOS it won't drive the bus - not enough power on lines. I would think the same thing might be true of the Amiga. Interested to hear if anyone has one working. The other problem with some of those faster processors is the cache. I've heard that just increasing clock speed on a 500 can cause loads of incompatibilites.
