Well if they are proper powerpc chips they're going to have a lot of common instructions and registers, probably an enhanced altivec (Similar to SSE) and a whole host of similar components. Very possible you'd be able to get OSX to boot through linux on the xbox2 (If of course they manage to get linux to boot on the xbox2).
I wrote a more indepth post herehttp://forums.macrum...?t=69440&page=5
These are my views of course and not backed up by anything other than heresay.
Apple, Ibm & Motorola own the rights to powerpc chips between them. Motorola was Apple's supplier of powerpc originally and IBM made Unix workstations with their chips. It was only recently than Apple switched to IBM for their supply. The chips made by motorola and IBM are binary compatible processors (Except maybe a few new instructions) and both are capable of running OSX. Powerpc is more than just branding it's a line of processors like X86.
If it's branded powerpc it's going to be binary compatible.
Edited by desertboy, 25 June 2004 - 06:28 PM.