Just posted in my Nikon D800 review is head-to-head resolution comparison of the Nikon D800 to the Nikon D3s, spanning ISO 100 to ISO 12800. This follows the ISO comparison of the same subject.
If you’re not a resolution slut, this might make you one.
The big suprise is what happens at high ISO. Wow.
See my Nikon gear page for D800 availability status.