Have just been reading through a number of posts on the forum related to the 5D mark ii crashing and or bricking (in the new emergency section). It looks like what I have described above in relation to my camera, is not isolated with several other users describing very similar issues after ML installation, albeit at different time points. (I.e. live view not working, fuzzy playback screens, camera not starting, not able to update firmware etc etc - see original post for details)
A common theme when things start to go wrong, seems to be when people are filming (as opposed to shooting pics). I wonder if this is something that the team at ML are looking into regarding the stability of ML2.3 on the 5D MK ii especially in movie mode?
I do appreciate the fair warnings given in advance for ML and also the work that has gone into producing it. I would love to use ML in the future as I think it's a great concept, but would feel quite hesitant to install again given my (and it appears others also) experiences. Just a thought in the spirit of continuous improvement.....when it worked it was brilliant!
In the meantime, I've decided to ship my camera to the repair shop at Canon - thanks for trying A1ex. I'll update this thread when my camera comes back (I hope) from the 'hospital'.