After cruising the various magic lantern threads for the past few days, I think I've worked out that the latest builds for the 7d version of the firmware are pretty stable and producing reasonable results. They've introduced a new "mlv" format that's supposed to reduce the number of corrupted frames. I installed the hack on my 7d and was able to record raw clips just fine with the mlv_rec module, but I couldn't get the mlv2dng converter to work on my mac.
The good news is that it looks as though this is coming along as a usable option for raw recording on the 7d. Someone posted a short that was shot entirely with 7d raw. The content is lame but the images are pretty amazing. Its not the best example of showing off raw, but I think it makes the point rather nicely. So much more cinematic than H.264 compression. The way that it handles the highlights in the background is pretty remarkable : http://vimeo.com/73835410