When the new Leica M was announced, this really got my curiosity up on how the M would work with non M lenses, so decided to experiment using my M9P (although shooting blindly with no live view).
I have a few old Nikon AIS lenses so I ordered a $39 Fotodiox Nikon-M adapter from Amazon. It came today and tried out a Tamron zoom with AIS mount using the adapter on my M9P, looking at Haleakala mountain off my backyard. Worked real well with focus set at infinity and shooting 200mm shots. I'll try my Nikon 50/1.2 AIS next.
This is really exciting, with the new M, to be able to shoot non-M lenses using a cheap adapter, all at full format.
Now I'm really itchy to get the new M.