Why?
It could probably be done yes, but it'd likely get the attention of lawyers at some rather large companies. You really don't want to piss off a company as big as IBM and cloning any PPC *will* do that.
What's more to the point is being on an FPGA it'd make the Sam440 and Efika 5200B look like speed demons.
Wouldn't it just be easier to use a real PPC chip?
