Me personally , I cant wait for Canon to create a Medium Format sensor , at least 35x46mm - It would be perfect for me - I am in love with Canon lenses and color , but really want to witness it qualities in sexy 40MP package !!!
Except that none of your EF-mount lenses will work with a MF sensor. The TS-E might cover the image circle, but once you put in a bigger mirror the lens won't focus to infinity because it'll be too far away from the sensor.
And then if canon do release an MF camera, and people have to upgrade body and lenses in one go, they then face competition from the very nice and portable Leica S2, Hasselblads, Pentax/contax/mamiya 645, and both Leaf and Phase One have 80 MP backs to compete with. (personally, if i had the cash, i'd be on a Leica S2 tomorrow).
And for all the people i've read whingeing about the sealing, AF and fps on the 5D2, so what? 7D is the sports camera, 1D4 is the better sports camera. 5D line has been and always will be low-fps, and lesser AF.
Give me the 1DX (or even 5D2) sensor in a cardboard body, 1 AF point, 3fps, no video, as long as it's got Live View. Because i'll be setting it up on a tripod and taking landscapes, star-trails, indoor low-light portraits with fast lenses, studio-benchtop-macro, all the things that my 7D is not built for. And price it the same as I paid for my 7D, that's about fair.
(i'd be so happy with a 5D classic, if it had live-view. or does it?)
Once you add in more features that everyone wants for the new 5D, it gets more expensive. 19AF points like the 7D, sealed like a 1D4, 8fps like the 7D, RAW Video, see-in-the-dark sensor. You can't have it all. Or you can. It's called the 1DX, and it costs $6800.
Bring on the 6D baby-FF please.