DigitalRev claims one of their sources says Nikon is going to skip the D700s, so they can make a bigger impact with a 16mp D800 (with the same specs as the D3s other than megapixels).
The go on to list specs including ISO 102,400 and 1080p video, and claim it will be announced by the end of this year.
The D3s was a big step in terms of noise performance. This proposed D800 would be another big step (keeping the same noise levels but with the much smaller photosites needed for a 16mp sensor). While (barely) within the realms of possibility, we'd be surprised if a D800 with these specs was announced before the end of the year.
Source: DigitalRev on 8/31/2010.