OP wants to upgrade his body, choices are 7D, 5Dii, 5Diii, 1Dx.
Telling him to sell up and get a D700 isn't an easy solution, economical, nor he might not want the hassle, nor he may not even like the bodies (ergonomics?). Not everyone wants Nikon. I get on fine without it, are you saying I or all these other people (Lara Jade, Jeff Ascough, Emily Soto), shooting 5Dii should swap over the D700?
Nikon isn't the answer to everything you know and who says they will always be on top or actually on top at the moment? Yes the D700 is better camera than a 5Dii overall for a photographer. And I said ever since it came out is they need a new body like a D700 and everything will be "fixed" because they have a better lens back catalogue IMO (and lets not drag the whole 50 years of MF lenses into it....) and look what happens? A camera better than the D700 has come out call the 5Diii.
So what's the problem? Does the fact that the D800 is on the market makes the 5Diii a camera?
Leave the Nikon fanboy stuff at the door and answer the OP's question, I don't go into a Nikon thread and recommend someone to swap system, I really don't know why you do this to people with existing Canon gear, i don't think this is the first time either. It would be a different matter if he are starting from scratch, but he isn't.
Please don't make me quote my first post, YET AGAIN.