My Best guess is $6200 for the D4.
This talk about the 9 cross sensors up-to f/8, I think what's missing is the specs on the other cross-type sensors that will be operational up-to f/2.8 and f/5.6. I'm sure there will be a slew of these cross-type sensors. We really don't need more than 51 total AF points, but if Nikon can improve upon the industry's best AF system by adding even more cross-type sensors, it will be a winner and all we really need.
Native ISO of 102,400? Oh. Em. Gee. If 102,400 is as clean as ISO 25,600 on the D3s, I'll be amazed. I know that's a 2 stop improvement, but Nikon is increasing native ISO by 3 full stops! I can't see them making that big of a jump in NATIVE ISO if they weren't able to achieve at least 1.5-2 stops over the D3s. Who knows, maybe they were able to increase SnR by a full 3 stops? My other question is DR. I'm preparing for at LEAST 14EV of DR in the D4, maybe even 14.5EV. 16bit RAW would be nice, too. :)
I'm all in for a D4. I know I'll have my hands on one at some point in the near future - exactly when, remains to be seen. I'm hoping for a early January announcement with the first shipments in early to mid March. Let's see what happens!