An interesting couple of articles from Chipworks [via *********]:
http://www.chipworks.com/blog/technologyblog/2012/10/23/full-frame-dslr-cameras-part-1-nikon-vs-sony/
http://www.chipworks.com/blog/technologyblog/2012/10/24/full-frame-dslr-cameras-canon-stays-the-course/
Refreshing to actually read some facts amongst all the rumours and speculation. The second part throws some light on why Canon seems stuck around 20MP and what the future might hold.
What this could be indicating is an intention on the part of Canon to skip 0.35µm and possibly even the 0.25µm process, and move directly to a 0.18µm. I have my doubts that Canon can sustain another generation of full-frame sensors on the 0.5µm process.
APS-C would however be the area for Canon to test a new fab. The stakes are lower bringing a new sensor into the APS-C market, based on production from a new fab.
A lot of people are betting that Canon will launch a new line of APS-C sensors next year. It will be interesting to see what an analysis of a new APS-C sensor yields.
By sticking with a mature fab, Canon does seem to be playing a commercial game to lower its costs, and possibly try to build in more headroom in terms of margin.