Rangefinderforum, although if you aren't a member there already it might be difficult. That's probably the most active market for old RF gear that I can think of. I also see quite a bit of old Leica gear on Gumtree, no idea how strongly it sells for though.
We don't really have many Leica film users here, I know there's a few M4, M2 and M3 owners about but they are rarely the main/sole camera for that person. Additionally, people tend to either be in the market for bodies or lenses with Leica gear... rarely both in a combined package.