A Canon EOS 4K SLR is on the way. We just learned about the $US20,000 Canon EOS C300 Digital Cinema Camera due out next March. Canon has also released some details about a video-oriented SLR, and we're drooling.
The Canon EOS 4K SLR is just a concept now, but it's pretty exciting. We do know that it'll have a full frame CMOS sensor, and that it'll record 4K video at 24fps, but that's about it. No word on pricing or availability, but Canon is definitely targeting the professional production set with the concept camera.