As I have said in other threads, the D300s is still listed in Nikon's catalog. If they discontinue it and do not announce a replacement, THE the D7X00 class of camera's will be it. As long as the D300s is a current model, I think there is a strong possibility that the D400 will eventually appear.
While very impressive, the D7100 still does not have some of the key features of a Pro body. For instance, put a L-bracket on one and try mounting it on a tripod in portrait orientation with a cable release attached? Put the D7100 is a D300s body with its controls and connections and you've got a winner in my book. And given recent pricing, it may come in the $1600-1800 range.