Where are you based?

"The Real Camera Company" on Dale Street in Manchester is a real Aladdin's Cave of a place when it comes to rangefinders (of most varieties) and lenses for Leica thread (LTM) and Leica bayonet lenses for the likes of the Voigtlander R series cameras.

You'll need to check what bright lines appear in the R2's viewfinder when selected. I think it's 35, 50, 75 and 90mm lenses but do make sure as there'd be no point buying (say) a 21mm or 28mm lens unless you also get a hot shoe viewfinder to go with it.

The other alternative is to look for something like a Minolta CLE. These are great little cameras and offer a relatively cheap route into rangefinder potography.

Being ever so slightly radical, you could also do worse than audition an Olympus OM1n (or OM2n). Yes, I know it's an SLR but it's only a tiny bit bigger than a Leica M6 but it's massively cheaper and has an exceptionally bright viewfinder with 100% coverage and a superb range of optional lenses. Unless it MUST be a rangefinder, the OM1n/2n are fantastic alternatives, very portable and can be the base for a great system if you choose to build one.