Hi,
I've installed ML on my 650d this morning, everything (almost) work fine, thanks to the developers !
Sorry if I repeat things, but I haven't read the 20 pages of this post

The way the bootdisk flag work on the camera is interesting : if the SD Card in the camera is not bootable, the original Canon firmware is launched. So for enable/disable ML on a SD Card you just have to change its bootflag, no need to touch on the camera. (I say this for people who did'nt notice this feature... At least it work as it on my camera).
3 little questions :
- I am probably missing something, but where is the "play" button on the camera ? (used to re-call a focus point for example).
- I plan to buy 32gb class 10 SDHC (Lexar 400x) ... No problem with ML ?
- Does any sdk isset for control the camera with PC through magic lantern ? (I'm developing a scriptable application with canon SDK, mainly for assign wireless controller buttons like Xbox360 Controller to camera functions, but Canon don't allows you for exemple - if i'm not mistaken - to access in live to focal and focus ring position).
Bug I've noticed : focus picking doesn't work while HDMI display is used.
Thanks.