The Nikon D800 is likely to be announced 7 february based on information from nikonrumors.com.
The D800 will likely get a magnesium alloy body with more sealing rings. It is 100gr lighter than the D700.
Shinji Watanabe’s Flickr stream, had one photo believed to be taken from the D800 at ISO 6400, 7360 x 4912 from 36MP sensor.
Click on the photo to see original size, it seems there is some motion blur from the model movement therefore not all parts of the image are sharp.