Let see how those bulldozer cores v2 /piledriver fare before discarding them

BD had good perfs in high threaded workloads better than Athlon II if memory serves right.
BD also have better SIMD than Atlhon II or the cores in llano.
If Sony goes with two pretty much off the shelves products there indeed may be better of with a std CPU+GPU set-up.
I was thinking of an APU + GPU a while ago for the xbox (based on the double gpu rumors) but I was expecting a pretty "tiny" SoC (max 170sq. mm).
Llano trinity both are ~230 sq. mm not tiny cheap.
High end SKU consumes also a lot (100Watts of TDP could be more in real world).
Overall if I put schedule issue (more a risk than a fact but a significant one) aside a reworked Kaveri make more sense than a llano + Kurt set up. The weak part in Kaveri is the ddr3 memory controller but I guess it would be pretty straight forward for AMD to replace it.
The issue is AMD delivering on schedule, they have experience with TSMC so it's possible but say they have a new bug in the CpU somewhere or something like that... they won't have time for work around or will have delay.
WRT the gpu In case of a std cpu+gpu set-up, I would discard anything with a 256 bit bus. So a reasonable bet would be a part akin to cap verde or a bit better. Cap verde may top at 12 CU, a replacement may go up to 16 CU. I would expect a CU number between 10 and 16.
EDIT
The more the time passes the more I believe that KB-smoker may be right on that, the 360 came together only a few months before release.
If there is truth to the rumor, Sony may had this 6670 gpu to the devs kits to make up for the lack of raw power and bandwidth of llano.
Kaveri with 2GB of GDDR5 (as more is problematic) should perform / out perform the said solution.
FLOPS comparison are apple to orange between previous vliw5 architecture and the new gcn scalar architecture, you may want to remove 20% to the peak FLOPS figure.
A8+ 6670 is 480+768 so 1248, minus -20% that's 998 MFLOPS. even if kaveri end south of that by a hand few FLOPS or even one hundred FLOPS, it should do the trick.
I got to research more about those stream roller cores I don't know if there BD base like piledriver or based on older architecture.