Here is a link to a VERY interesting technical documentary comparing currently available single-chip movie-capable cameras, including the Canon 7D, 5DII, and 1DIV. Well-done, interesting, and extremely educational. Part 1 of 3, the rest coming in the next 2 months.http://www.zacuto.com/the-great-camera-shootout-2011/episode-one
I know this is not exactly a rumor-based post, but the clip does give one some insight into what the Canon engineers are up against, and what areas they will likely be trying to improve in forthcoming movie-centric camera models.
Have a look, the results may be somewhat surprising, especially concerning how the Canon cameras compare to each other. I'm not a movie guy, but still thought this was pretty good stuff.