Personally I would prefer a 8610 @ 1330MHz over a 8640D @ 1 GHz over a P1022@1 GHz.
I think bplan should know pretty much about the 8610 already.
In principle I guess Freescale will shift entirely to QorIQ in the middle future, but before that transition is done and e600 gets abandoned I would like to see a new e600 system. And IIRC the QorIQ have some fpu weakness. They are no desktop processors, the e600 was designed for the desktop.
The 8610 is the easiest chip to start with, the price is fairly okay. The 8640D is not hat much more expensive, should be faster per core (bigger L2 cache) at the same clock. In future MorphOS has to cope with multi core cpus anyway, maybe the 8640D would be a good starting point for that endeavour.
I like small boards with integrated gfx, with the 8610 this is possible. For those not satisfied with the inbuild gfx unit, there will be the option to insert a gfx card into a pci-e slot. An 8610 system should provide 2-3 slots. Only one slot is too few.
The redtail design by NEC may be a good staring point to derive a small and pretty system from. I was thinking of getting in contact with them, but haven't yet.
In the end I am only interested if MorphOS will run on such a board.