I just think this thinking takes for granted that companies always follow the same gameplan. What we've learned from the last 5 months from CanoNikon is that they don't. They release models. Then leapfrog them. They retreat on some specs. Some specs get turned up to 11. Other fizzle at a 3 or 4. They don't add obvious enhancements (IS to a standard L zoom lens??) then add the enhancement in the strangest places (28 and 24mm non-L lenses??).
I think the whole thing is very unpredictable. All we have to go on are a couple of very good pictures taken int he field of a protoype (near finished) Canon model that looks like it merges the features of a the 7D and 5DII into one body. The rumors suggest 22-24 mpx. Why Canon wouldn't use it's 18mpx sensor it developed for the 1Dx, I have no idea. Why Canon wouldn't recognize the needs of a large segment of photographers and up the resolution beyond 21mpx meaningfully, I have no idea.
Why do either of these companies do what they do is in many ways beyond me. But I don't run them, make decisions for them, or even serve on any focus groups for them.
All I know is Nikon just released the camera I want and I preorderd. And Canon hasn't shown its cards.
Regarding bodies, what I hope Canon will do is to introduce two new bodies this year, and the rumours suggesting that there are different prototypes being tested make me hope this might even be the case - after all Canon probably realizes it cannot make everyone happy with a single offering.
So, if I speculate about what Canon might be offering in the $2700-$4500 range, this is what I would predict:
On one end there would be a high-MP camera for landscape/studio photographers, meant to compete against the new Nikon. As someone pointed out, a 40MP camera would also be the right size for 4x4 oversampling - very convenient for top-notch video performance. For this market, it should be possible to sacrifice high-ISO and FPS performance - that is not the primary need of the potential customers for this one.
The other camera would be the "junior" version of the 1DX - a little less of everything. Smaller body, single Digic, single card, 22 MPs, and maybe 6-7 fps, but with a much improved focus system compared to 5DII and a very-good high-ISO performance. Some people might see this as a FF upgrade for 7D users as well.