I've got several rangefinders, sadly no Leica yet.
I do have a Voigtlander Bessa R2 which I love. But, as you mention it's not quiet which is probably it's worst point, however it's not as loud as your average SLR. Also, it sounds louder as it's only a few centimetres from your ears! Apparently, the newer Bessa R2a & R3a are noticeably quieter.
The Voigtlander lenses are generally superb, especially for their price, (the only lens which some people don't like is the 50mm f2.5).
I expect that some of your problems focussing the Canonet may be due to the fact that the viewfinder and rangefinder patch need a bit of a clean -- a common problem with these 1970s cameras.
The focussing on the Bessas is very easy as the viewfinder/rangefinder is very bright.
If you're starting to dream of a Leica, what about a second hand one? Still more expensive than a Voigtlander but an M4-P with a CLA may be a good choice for you?
By the way the Hexar is a rangefinder, it was discontinued Oct 2003.
I assume that you've found Stephen Gandy's Cameraquest site? If not try www.cameraquest.com for loads of rangefinder stuff. It's also the best place to buy Voigtlanders from in the US.
Hope that helps!