Yeah, the only thing I can think of is to get a cheap G4 CPU online, like one that came out of a sawtooth or something. (I looked at pictures and they theoretically should work. both computer having 100mhz fsb.) Probably look on eBay or something.

That's all I can think of. Since you've tried basically everything else. Probably would work too. I hope.

Anyway, hope you get it working! And merry Christmas!