all recent ppcs are arm or xscale, all arm should work on xscale, but as youi said it often doesnt, plus the leader in the field for a long time was the ipaq and it had somer really dumb hardware/firmware issues you had to work around, making cross ppc compatibility harder
mame is also available.
scion, not sure if you are just trolling or serious, but a ppc is not a laptop, same as a notebook, palmtop and desktop are all different
plus they ain't all that cheap
