Surely though there would be a large market for the pros who want a compact back up body with similar AF and FPS rates & features.
The D700 delivers that. The Canon misses that market by a mile.
?? Sounds like clutching at straws to me.
A pro would most probably want the vertical grip. I've compared a compact body with an attached grip to a full on pro camera body. The attached grip will simply never feel as comfortable, and in the pro market that's going to be a serious consideration.
For a pro that wants the AF and FPS, the 1Dmk3 really does take a lot of beating. Go read up on it's picture quality, it's meant to be the dogs nuts despite not being FF.