Quite, in fact. If I had that kind of money, or maybe more, I'd go for both (M9 and Monochrom). Why not? I'd love to get my hands on one and limit myself. It's true that with time one can "identify" what would work as a B&W, even if taken in color. The price issue, though... I've even considered the Fuji Pro, (thinking it would do me some good to re-learn the rangefinder method) but I won't go for it. Things are a bit tight. I would love to go out with more than one or two cameras, but there are back issues too
What I don't like, and can't think of any good excuse except making money, are all those special editions (the Chinese ones and the Hermes - don't know if there are others). It seems to me that Leica does a disservice to itself by doing this since Leica cameras are legendary workhorses and not "jewels". But then again, I have the same conflict with watches: Rolexes with diamonds and all that... So maybe I'm too purist.
The Monochrom is a serious tool, as far as I can understand. Very courageous move also. I do wish it would succeed and maybe followed by other manufacturers. Maybe a Fuji, less expensive wannabe?