It depends how brave Canon want to be.
They've obviously found the magic formula for downscaling from a high-rez sensor.... They could trickle it down to their cheaper cameras and pretty much kill off any threat from Nikon/Panasonic etc for video work (for now).
But then people would be far less likely to buy their flagship models like the C300 and the 1D-C.
Canon are pretty conservative, so i imagine it will not happen for a while yet. Maybe, just maybe, they will allow it in the 1D-X and 5DIII