<<People are demanding the 2 ton load capacity Enzo Ferrari for the price of a pickup truck.>>
Absolutely and I am sure Nikon know this and they also know that there is a large potential for a D400 semi pro camera. They will also know that Canon users will also be discussing very similar scenarios. It's just a case of who blinks first! If it does materialise, then I believe it will be what the current D300s owners want, not those that dream of a what is really a concept camera. A "nice" concept, but not a realistic one.
We will see in time, one way or another, but in the meantime I have a great camera capable of both FX and DX crop images, but a faster DX could make the pairing complete