First, let me say, I'm not trying to start an argument by any means, so I hope you dont take it as such TM. I'm just exploring possibilities.
That said, I'm not familiar with the other computers that use the same IBM PPC chip. Such hardware is obviously obscure, and is not something in the home of the average computer user. As such, nobody is going to spend the time to get OS X working on them.
Apple can certainly take plenty of steps to prevent allowing OS X to run on anything other than Apple computers, just like Microsoft took steps to prevent any OS from running on the Xbox except their own. Over time, and with a little tenacity, this protection was circumvented. Now you can run any X86 OS on an Xbox. For example.
Though, I guess we will find out for sure soon enough
