It will be interesting to see what Canon can do (or will do) with the mirrorless. There are so many suggestion (read it s demand) in this site: smaller size, reasonable priced, BIG sensor, small zooms etc. Unfortunately, they mutually exclusive. I am interested in seeing how fast is the AF or does it comes with MF and aview finder ( like the M9)?
The specs are not mutually exclusive:
1. SIZE - no problem
"FF" (36x24mm) can be packaged in a very compact and very high-quality camera without any problem.
example: 124.5 x 77.5 x 32 millimeters, sturdy metal body, weight only 13.405 oz./380.1g with batterieshttp://www.cameraquest.com/cle.htm
2. LENS SIZE - no big problem
just look at M-mount lenses not only from Leica but also from Voigtlander and other manufacturers. Even a decent f/4 kit-zoom could be made very compact and with decent optical quality. As a matter of fact, no need to develop a new proprietary mount. Just take the patent-expired Leica M-mount and electrify it, using Canon pin layout and mountr-lens protocol. It would be backwards compatible with M-mount lenses w/ manual focusing.
3. FAST and 100% ACCURATE AF - no problem
Just take the approach of the Nikon 1 hybrid AF sized to FF. Take the 5D 3 sensor, take 10.000 sensels out of it for in-sensor-plane Phase-Detect AF for ultrafast stage 1 "pre-focusing" and then hand over for stage 2: DIGIC 5+ powered, fast and 100% accurate Contrast AF. All back-/frontfocus issues with any lens will disappear. No need for microfocus-adjustment.
4. VIEWFINDER - no big problem
Take the Fuji X1-Pro approach and make it REALLY RIGHT. Take the best available 3 Megapixel OLED plus parallax-corrected optical viewfinder. Users decide, whether they want to use optical, electronic or combination in a specific situation.
5. PRICE - no problem
same sensor, DIGIC, electronics and many other components from 5D 3 but minus the entire mirrorbox assembly (demanding very minute alignment = labor intensive) and minus prism. Therefore price should be somehat less, lets say 3 grand USD / Euro for starters.
Now, if I can think of this camera, Canon should be able to figure it out too and build it. :-)