Well, you could look at thge reference takemehomegrandma made (or just take his word that ARM is the way to go).

Personally, I'd side with you in that I'd like G5 support (and maybe even e6500 support). And SMP via an additional box does make sense.

The thing is, with two seperate concurrent boxes running, I don't think you'd have to break with compatibility. Abox would just run on one core, while Qbox ran on the remaining cores (kind of a weird combination of SMP and ASMP).

And if an ISA change does ever occur, I'm with those who favor ARM. X86 is just too convoluted.