Canon has shown a 29.2 x 20.2mm size 13,280 x 9.184 pixel CMOS camera sensor. It can also do full HD video from any 1920 x 1080 pixel area of the sensor.
Now the mind boggles at a 50D type camera with such a sensor. The real issue has to be the lens resolution, unless they are doing something like 4 pixel sampling to get better colour handling.
The march of progress continues.