Actually an FX sensor with the identical density of the D7000 sensor would be about 37.6 mpx. No need to stuff another 4 in
The multiplier from DX-->FX at the same pixel density is roughly 2.35, not 2.
I'd rather see a D800 with even better noise performance than the D3s. A high megapixel camera should be a split-off from the D700 lineage; a specialty camera, because it will always be noisier than it could be at lower density. The idea behind the D700/D3 was "do it clean, 12 is enough". That worked for me.