@Jope:
In theory that is completely possible. You could make a card with a standard socket for an Athlon, or P4. You'd have to have a flashrom that initialises the card, and launches a JIT 040 emulation and then sets about executing kickstart. I'm not sure you'd get your R&D money back, though, and I'd rather get a G4 to run OS4 on :-).
Oliver Day will be solving similar problems getting his coldfire card running.
