>I would gladly pay $5k tomorrow for a D4 body with a D800 >sensor in it.
Wouldn't you expect to pay more than $6000 then, to get all that a D4 is with more pixels? Processing horsepower alone would be a lot more than the D4 is now.
What I'd like is a D4 with a D800 sensor (or more pixles) and BINNING, so that when you need less pixels you combine 2 or 3 or 4 pixels at the sensor level into one readout. Much lower noise than what they do now, and flip the button and get resolution instead. Astro cameras have been doing it for years.
Cropping as a way to less pixels is very limiting.