That's pretty much been a rumour ever since the D3 came out as it's usual for Nikon to release a camera aimed towards the PJs and Sport shooters and then one with more MP and less fps aimed towards studio photographers.
Only time will tell, maybe the Photokina will put an end to this not so much of a rumour :wink:
Actually, that rumor has been around quite a while now. Ever since the first iteration of the D3 upgrade came out with "D3x" hidden in the code and showing full (24 Mpix)plus cropped frame sizes. A camera shop in France has it listed for pre-sale now too
I think, in the D3, Nikon has produced a body that combines all the features needed to be classed as either and 'X' or an 'H' model and I think Nikon has said that quietly. Any new body about to be released will have own designator.