My feeling is that Canon is planning a camera with a sensor larger than the G12, but not even as big as the Olympus 4/3rds sensor. The reason behind that thinking is that lens physical size becomes larger as the sensor does (example the Sony NEX). Currently the G12 lens is not physically so large, so it could stand some beefing up, but don't expect manual zoom, or a focus ring, nor a fast lens either. This camera is more likely to be a Nikon V1 smaller with a fixed lens, and fewer controls. It'll be what Canon says, almost a super G12 i.e. a bit bigger physically, with a slightly bigger sensor, but with all the current aspects of the G design.
Personally this is not what I am looking for and I'll probably stick with the NEX as a compact alternative.