I think the 7D Mk II needs to be put to bed now. In my view Canon would be mad to bring out the 7D Mk II as sales are still doing well and its not nearly reached its end of life. It doesn't need to be replaced or upgrades right now. Its serving its purpose on the market so Canon wont touch it just now.
With the C300, Canon made a statement about how the time to bring it to market was a record short time for them at around 2 years.
It's more realistic to assume that a camera takes 3 to 4 years to bring to market and that they arrive in the market place when they are finished.
Lets assume that the design work on the 7D Mark II started before the 7D was released as the tail end of the project schedule (lets assume 3 months) will be for ensuring that production is ready, working, marketing knows what it has to do, etc.
So in September 2009, Canon announced the 7D, even as it is likely that the 7D mark II was already being talked about inside Canon. The roadmap for the project will have been laid out assuming that everything would proceed according to plan. Assume the same for the 5D Mark III. Now throw in a couple of natural disasters (earthquakes, tsunamis, flooding) and a man made on (nuclear reactor) just for good measure and project plans are suddenly obsolete with respect to a final delivery date - but not the product itself.
So at this point in the project we're maybe a year out from the 7D mark II being released. In light of that, the camera design has probably been whittled down to just a few different models that are now starting to find their way into the hands of testers and over the course of the next few months, feedback on usability, image quality, etc, will make its way back in and one will be chosen.
Whatever the number of megapixels are now, it is likely too late to change it as it would mean a new sensor and new circuit board design for the camera internals.
Similarly, delaying its release is not something that they will have planned for and that it will hit the market irrespective of how good or bad the current sales of the 7D are.
Delaying the product risks moving it further out into the future where its feature set may be more vulnerable to other, newer, cameras, that started design later and are thus able to use new components, etc.