I agree with Denzil. My interpretation of everything Nikon has done in the last three years suggests that Nikon is pushing D300 users (who HAVE to have the pro controls and AF-On, 51 pin, etc) to FX. I think they're done with "pro" form factor DX. Must not be enough market for it. Also, I don't think what we're asking for is possible. We're never going to see another Nikon DX sensor under 24MP, and it's pretty apparent that you can't get 8FPS at 24MP, with current technology.
The D7100 does everything well enough to qualify as a top-notch DX action camera. It shoots 6 FPS, which is enough for anyone not shooting for Sports Illustrated. It has nearly all the external buttons (other than AF-On) needed by anybody (they're just in a different locations). It has the cam3500 AF system. As for the buffer, if you have to fire 15 frame Raw bursts to shoot action, then yes, you need a D4.
I have a D7000, and I think I might have one more DX upgrade in me (then my sons will be done with High School sports, and I'll have no further need for DX reach). If Nikon releases the D400 that we all hope for, at something less than a king's ransom, I'll give it serious consideration. If this doesn't happen by next year, I'll get a D7100 for the improved AF, and my next camera after that will be the lowest level FX body available at that time. Other than youth sports, I have far more need for wide angle and high ISO performance than I do for telephoto reach.