My Fuji GL690 has a thirty year old lens on it. The idea that a Leica lens could be sharper is to laugh. I simply do not possess equipment that can demonstrate optical defects in that glass wide open and handheld. It is sharp right down to the grain.
It is, however, a gigantic heavy beast, which is an issue, and at 8 shots a roll and with an f/3.5 lens there's a lot of shooting that it's simply inappropriate for; these dovetail well with Leica strengths in that there are a lot of very fast, very good M mount lenses, and the rangefinder is a useful tool in low light. However, you're talking about bolting it to a tripod at all times, making this strength actually irrelevant. As a result, I suggest the Fuji 645. They are reasonably compact, get a reasonable number of shots to a roll of 120, and with three times the film area will crush a Leica effortlessly for quality. The major downsides--they are loud and the zoom is somewhat limited (and slow)--is actually a nonissue for you because of the tripod.