About the best is a Nikonos which is designed to be water tight to 45 meters (150 feet.) It is also often used by people in rough conditions (rain-forests, mountains, snow, hiking.) Its built like the proverbial brick outhouse and of course is heavy to match. Also it does not have a rangefinder but in reality that's OK as the lens has a special focus / depth of field indicator that works pretty well. The standard 35mm f2.5 lens is pretty respectable optically too. They can only be had second hand and as a consequence are not too pricey. Just get it checked to make sure its in sound condition. Sorry I only just now notice your preference for a small digital so this one is out.
