Yet Canon does not plan on either of these being the 4k cinema DSLR? Not going to lie, but this seems like a pretty good solution for a 5D replacement.
Wedding, low-light, movie makers, and even sports photogs can use the 5DIII for their purposes; yet when high iso speeds are unnecessary, such as in a studio or in landscape environments, the 5dX provides great resolution.
Interestingly, the 5DIII sounds more like what the 5dX should be (sports, speed, low-light, and movie hybrid), and the 5Dx sound more like the natural successor to the 5DII (landscape, high-resolution portraiture).
That said, I don't anticipate these specs coming to fruition.