I have received several tips from stores, Nikon reps, Nikon authorized service centers, etc about the Nikon D700x. Those tips are coming from different parts of the world and the interesting thing is that they all point to a Nikon D700x release in the Fall of 2009:
"I was at *** 2009 show earlier this year in ***, and was asking a staff member on the Nikon stand about the D700 replacement/upgrade. I was told whatever replaces it will be released in October/November 2009, but they would say no more than that."
"My D300 is in for service at Nikon (bad aperture control module) and I asked the tech when a new dslr was being released and which one. He responded with the D700x this fall. A 24mp replacement for the D700."
Nikon D700x NR probability rating: 40%
I believe there will be a D700 update this year, but I don't think it will be a D3x sensor in a D700 body (would you buy one of those for $6000)? I think we will see more of the D300s type of update for the D700.