Neumannfilms posted a video tutorial about how to use the Magic Lantern hack to get raw video from a Canon EOS 5D Mark III. You can download the RAW file, the H.264 comparison shot, and the raw2dng.exe file here. A tutorial on how to install Magic Lantern can be found here. They say:
The quality is really amazing in this raw video. I would compare it to shooting 1080p moving cr2 files which is the file type that you get with doing raw photography in the Canon cameras. So just having this option in the Canon 5D Mark III and other Canon cameras is just huge. Even if you’re only going to use it twice a year to shoot greenscreen work, having the option in the camera instantly bumps up its worth at least a few thousand dollars.
Neumannfilms produced the video below, Summer in Oregon, which shows what you can do with the Magic Lantern RAW hack.