There is a sudden spurt of rumours around a PMA launch of a Nikon D3something. The Nikonians forum, which seems to have some good contacts, has added "D3" to its D1/D2 forum and they don't seem to make changes lightly.
Anyway, if the rumours are true (and I've been waiting a long time for this to happen, so I have high hopes but I won't believe it until I see it!) the camera is in the 18-20 mpixel range with a 1.1 crop factor, plus a 1.5x crop factor in High Speed Crop (HSC in Nikon jargon) mode. This of course would render DX lenses semi-useless as they'd leave vignettes in the regular shooting mode.
There isn't a lot of other info yet, but any details would be suspect anyway since Nikon is tight lipped.
Rumoured launch is October/07, which for Nikon probably means it will be on backorder until March/08....