Originally posted by Digitalis and it has to be digital? why don't you get a Leica M3 or a Nikon SP and shoot film?
Because if you shoot film, even with the best lenses, you are still left with the tedious chore of scanning. Believe me, I know what that is like. For years, I shot with a Contax G2 rangefinder and superb Zeiss prime lenses, but the burden of scanning finally became too much to bear, and I made the jump to digital with a K10D. Being able to open images immediately in a digital editor was like being let out of jail. Moreover, the IQ was better than the best scans that I could make (and I was quite skilled at using a high-end desktop film scanner.)
That's why so few people return to film once they have gone digital.
Regarding a Leica M9 system, clearly one is pushing up against the law of diminishing returns with a camera such as that. Despite the excellent glass, IQ will probably not be very much better than with a high end Nikon/Pentax/Canon camera and their best lenses. If you truly want a quantum increase in IQ, you have to go to MF with all of its size, weight and cost limitations.
Rob