While it hasn’t exactly been a well-kept secret, the next Canon 5D has been officially announced.
Coming in with a 50.6MP full-frame sensor, Canon has finally pushed up against the limits of full-frame 35mm, and is aiming this camera straight at people who want medium format, but just can’t afford it, and want to keep using lenses they already have. The two new models are the 5DS and the 5DS R, with the difference being a low-pass filter cancellation effect on the R model, which should give even sharper photos (but the potential for some moire/aliasing). They also announced a new lens, the EF 11-24mm f/4L, to presumably take advantage of this crazy resolution (many lenses will not be able to fully resolve 50MP).
The first thing we should get out of the way is that this likely isn’t a direct replacement to the 5D. We’re probably going to see a different 5D model with more video-focused features down the line. These new models are aimed squarely at photographers, and thus the video is limited to just 30fps at 1080p (and there is no headphone port). There is one video sample here, but it doesn’t give the whole story as it’s rather low-res.