There are various reports that Canon won't release the big 35+ mp camera until 2013. I've even heard the suggestion they'll come in at 40mp+. Canon does feel that their 20mp range for DSLRs is the best course for the moment. Customer demand will probably dictate whether or not they get into the big megapixel market. I do feel it's inevitable that it'll happen in the next 12 months.
There's a big price gap between the 5D Mark III at $3500 and the 1D X at $6799 that I think needs filled. APS-H is dead, so something has to go in there around $4500-$5000. Judging by the initial sales of the 5D Mark III, people are willing to pay a lot of money for high end digital SLRs.