The D800 image that leaked few hours ago on several of the official Nikon websites is now gone, but several readers noticed the folder named "Jan-Feb launches" that was included in the page source:
...File=/imported/images/02. Regional Marketing Centre/BV/04. Agency/JungVonMatt/148/Web/Jan-Feb launches/Q720/PPDD/Flash Assets/111125_SLR_Prof_Banner/698x209_DSLR--(Get Original).xml
Q720 I believe is the code name for the Nikon D4.
See the full Nikon D800 specs here.