Magic Lantern has been around for awhile adding great, non-standard features to certain Canon HDSLRs.  In their latest beta, Magic Lantern has managed to increase the bitrate achieving moderately stable 66 MBps and bursts of 74 MBps at 24p.

Hopefully we can continue to see improved firmware hacks that can open up doors for better quality acquisition.

Magic Lantern is a firmware hack that you install over your existing firmware, so use at your own risk.

Check out more info on Magic Lantern here.