A few things people are talking about confuse me.
Firstly, if Canon produce a higher MP 5D then it'll have to be more expensive than the 5D3 (as not to annoy people like me who have just bought one). Then they'll have their own version of the Nikon D800 that costs twice as much so nobody will buy it.
Secondly, if Canon produces a FF camera that is cheaper than the 5D3 then it'll have to be a lower spec. Say that of the 5D2. But Canon already have a camera the same spec as the 5D2... the 5D2. So why spend millions in development of a new product that replaces one they already have when they're going to sell it at the same price?
I'm no expert but I can imagine Canon releasing a higher MP version of the 1DX with a lower FPS. So you have one for the sports togs and one for the studio togs. They could then keep production of the 5D2 going a little longer to bridge the gap between the 7D and the 5D3. When the 5D3 drops in price or a newer and more expensive 7D comes out then the 5D2 will be squeezed out of the picture.
Just my thoughts.
Oh and following on the subject of weather sealing, my old 450D got rained on, splashed by swimmers, soaked by a waterfall and kept on taking shots. Nice to know my new 5D3 will take all that and a lot more though. Less stress about your equipment leads to better photos!
I'll have a good laugh if they announce a 1D series big-MP camera. What an amalgamation of the 1D series that would be...