The developer kit (intel Mac)
ThinkSecret has a report
on the kit. Of interest for us: Windows does indeed install on those machines - and the Mac OS X version does not out-of-the-disc install on plain vanilla PCs. I guess we'll soon hear from people trying to closely match the hardware used by the developer kits to see what the installer's actually looking for.
The murmuring is that eventually, someone will come up with a way to get Mac OS X to run on the "any-PC". The first try would probably be to install Darwin on the PC and then replace parts of the system by one of a "real intel Mac"'s.