That eDRAM isn't gonna shrink. Plus, my money is on TSMC as a manufacturer as Renesas seems to be gradually getting out of that biz. So combining the SOI IBM CPU (w/ its own eDRAM) with an AMD/Renesas CMOS part on one SoC would seem to be out of the question.
I wonder how far along AMD's ARM/GCN SoCs are. On 20nm or 28nm, I think they could get 128 alus down to 4-5w after playing with clocks. That is as long as my hunch is correct and they go for a small/medium tablet form factor.
Damn, that's alot of acronyms.