since there are mtf to eos adapters, you should be able to mount your leicaR (with eos adapter) on that adapter wihout any problems....things might get a little unstable though and i don't think it is a good idea to use more then one adapter....but that's just me...
i have used leica R lenses on the 5dII quite a bit, there are even some adapters with focus confirmation.....works well....will definitely look into that with the BMC...
i don't know of any mft to leica R adapters, but there is no reason why it should not be available...