Straight from the horse's mouth:
http://www.canon.com/news/2013/mar04e.html
It's apparently a 36 mm full-frame sensor that uses 19 um pixels - which I think works out to be approximately 1080p video resolution.
There's a sample video - it's quite impressive, especially the Geminid meteor scene.
Apparently it's just a prototype at this stage, with no immediate plans for production.