Originally Posted by BurntPork
Meant to say not over 800MHz for Sony and Microsoft.
Sony: 1152 @ 800MHz = 1843GFLOPs
Microsoft: 1280 @ 750-800MHz = 2048GFLOPs
Sony ends up a bit below, but not that much. Certainly not enough to bottleneck it. Nintendo, however? Unless the final box is much bigger, don't count on such high clocks.
I'm sorry but those chips would run much hotter than a 640sp @ 800mhz, the size of AMD chips with 1280sp in their current GPU is 212mm^2 (the HD 7870) it has a TDP of 160 watts @ 1ghz.
The size of AMD's 640sp in the HD 7770 GPU is 123mm^2 it has a TDP of 80 watts @ 1ghz.
Basically it has about HALF the TDP for half the sp. Your chart would look like this if taken my points into consideration.
Sony: 1152 @ 800mhz ~110w TDP = 1843GFLOPs 
Microsoft: 1280 @ 800mhz ~122w TDP = 2048GFLOPs 
Nintendo: 640 @ 800mhz ~61w TDP = 1024GFLOPs 
Considering none of the console makers will use the heavy GCN architecture, we can probably shave off 20% of the heat, leaving you with the bracketed numbers above, now if these were embedded parts (as they likely will be) they could shave off even more heat, but it's easier to do this sort of calculation with a chip in mind, which is why I used the e6760 as a starting point.
Your belief that the Wii U couldn't handle a chip that hot (~50watts) is just wrong, having half the shaders basically means half the size and thus half the heat, and as many people in these threads have said in the past, the size of the console won't limit the TDP as much as people might think, it's all about air flow.