Quiet agree and I'm in the same boat. I'm not disputing the number that DXO comes up with but #'s don't always tell the full story under all sorts of conditions. I've shot 1000's upon 1000's of files under demanding low light conditons with the D3s and have tried out the D4 and a borrowed regular D800 (before I purchased my own) under similar conditions and on the whole, the D4 and often times the D3s had more than just a single stop better ISO performance...sometimes considerably more. Yes, it always depends how one meters and shoots but in the real world under extrodinary fast paced performing arts and TV specials where lighting is changing moment to moment, the low light, high ISO shots that were consistantly useable, that didn't need enormous post processing work for noise, were the D3s and D4 files. The D700 did fairly well too although somewhat behind those two.
Thats why with a smaller file size (24mp vs. 36 mp) and fatter pixels that the D600 should have, I'm hoping if Nikon could pull the quite remarkable higher ISO performance they accomplished with the D800, then maybe they could up the ante and provide a stop more than that with the new D600, along with a somewhat faster frame rate and easier size files for what I and Guy just mentioned. Sort of a body that in these particular catagories (resolution, higher ISO performance and relative file size), fits between the D800 and D4. If this is possible, then it would be a nice companion for some to their D800 and for others that don't want a large pro sized D4 type body, a alternative.
As for imporvements in the various focal length lenses Guy mentioned, I am quite in agreeement. Nikon need to address these single focal length lenses and zoom, especially if used on the D800. Although the Tamron 70-300 VC lens is not a constant f4 zoom, at the very least, it runs circles around the Nikon 70-300 VR for travel and priced when rebates are available at a more than reasonable price and does quite well on the D800.
Dave (D&A)