Unlike Canon, Nikon's FX camera(s) can use a DX lens. Either in FX or DX mode. In FX mode you'd have vignetting, but maybe you wanted to go that route for some reason....
Personally I'm wondering if a) Nikon is going to try a viral campaign by unofficially leaking these things out there and/or b) if they really are going to put their foot down and not increase the MP.
The tradewinds indicate that the 5DII will have a 15-16mp sensor, and like I've said before: people want quality over MP, but the manufacturers are still semi-caught in a MP war. A 12 mp full frame with the D3's low light capability is going to continue to impress. All Canon has to do is put the 1DMkIII's new microlenses on the 5D's sensor and you would find a camera that would be bored in the Haunted Mansion because it would be too easy with a 1.2 lens. But I'm thinking they aren't that...smart.