Roger Galbraith photography have been allowed to put a recent Canon
white paper on the web.  It can be viewed here:
http://www.robgalbraith.com/public_files/Canon_Full-Frame_CMOS_White_Paper.pdf

The timing and content of this white paper is interesting.
The content includes what is (IMO) some superfluous discussion about the
advantages of full-frame.  Superfluous (IMO) because I would have
expected most photographers considering the full-frame vs aps-c debate
know this stuff already.  However, much of the technical content of this
white paper is devoted to presenting Canon's view on why CMOS is better
than CCD for large sensors.

It is nothing more than conjecture, but the timing of the release of the
white paper and content of it are indicative that Canon are likely to
have a new competitor in "full-frame" dslrs, and that competitor is
likely to use CCD sensor technology rather than CMOS.