It's been awhile
I hadn't heard much about the 5D Mark III for a while, after the excitement surrounding the 1D X and C300, I can understand why.
The information below comes from various sources on the web and in my inbox.
Two different pieces of information put the camera above 30mp. I get the idea there is more than one sensor being put through the paces. It will not have a pro AF system. It was suggested by one person that the AF will actually be a lesser version of the 7D autofocus system. The camera would not have a crazy frame per second rating, something in the 3-4fps range like the current 5D Mark II. It will be equipped with the DIGIC 5+ processor and be aimed at high megapixel/high ISO performance. The 5D Mark III will not be the 4K Cinema EOS prototype Canon previously announced was in development. There were no details given about the video functionality of the camera.
Most everyone is saying do not expect an announcement until at least March when the 1D X should be shipping. Announcement dates can always change though. It may depend on what Nikon does with the D800.