This is from a thread over on dpreview by Mlammerse. Jeff-C comments that he doubts the "D700x"will be called "D800" to which Michel responds with the quote below. I think the D500 sounds interesting, but another DX prosumer camera so close to the D300S upgrade?!
"Me was promised it wlll not be named D700X. I hope so, otherwise it will cost me some wine!
Furthermore I heard it will not have 24MP and also not the same sensor due to problems with video and that the it will be 18MP.
These are the names I heard last week again (I always ask once a week about news and which should come out in 2010.
A new wide angle prime lens
A new mid range zoom lens with VR
A super tele zoom lens with VR
No details yet
EDIT: the only detail I heard is that new Nikon items will be there in February 2010, don't know if February is a special month for Nikon, I'm not a Nikon guru and don't know there release history by heart.