I'm just trying to picture what the product roadmap would look like.
As it is now, the 650D/T4i has taken some features from the 60D and added some new stuff. This means that the 70D should move up into the slot of the 7D or just utilize the 60D body and add all the new technology from the 650D/T4i and the AF from the 7D and maybe use a slightly better body construction. So I was thinking that the 6D would share a similar body design with 70D but add the FF sensor and some other minor improvements for double the price (around $1000-1100 for the 70D and $2000-2200 for the 6D). Maybe Canon will compromise weather-sealing a bit (something similar to Nikon D7000?) to maintain a lower price point.
It might be wishful thinking but it makes sense to me. Will it cannibalize the sales of the 5DIII? Maybe. By the same token, shouldn't the 650D/T4i cannibalize the sales of the 60D and the 7D? I think the 5DIII would still have enough differentiating factors like a bigger body, better weather sealing, superior AF, faster FPS, bigger buffer and CF+SD if Canon made the 6D use SD only. The video features (especially if Canon ended up developing some Hybrid AF like the Rebel's) might be better than the 5DIII but that might be an opportunity for Canon to capture some of the 5D2 crowd who are mainly interested in video and finds the 5DIII to be too expensive).
I realize that the Nikon 39-point AF only has 9 cross type points. I was talking about the rumor that says it will have a 51-point (15 cross type point) AF similar to the D300, D800 & D4. Would Canon be content with just the 7D AF or will they up their game. In any case, the latest D600 rumor doesn't seem likely as people have pointed out that the screenshot comes from D800(E) manual and not really related the D600.