Received a brief bit of information regarding the upcoming Canon Cinema EOS 4K DSLR.
Apparently it won't be available for purchase until Q4 2012 or early 2013. The announcement could come some time before then. Variations of the camera are in the wild, no specs are known beyond the 4K specification for the movie mode.
The form factor will apparently be in the form of a 1D style body as shown at the C300 announcement.
NAB 2012 is coming up in the middle of April, and we have heard nothing about a possible announcement before then.