that's called "brassing" and, as the man said, many people find it attractive as a sign of a much used/loved camera.
Replating the baseplate is theoretically possible but would be prohibitively expensive. There's a few guys who custom-finish Leicas, but those are Leicas and the service costs as much as a Leica.
Paint would always look like paint. If the camera works, use it -- look at it this way, as it is, you don't care if it gets scratched.
consider eliott erwitt's M3, a thing of beauty if ever there was one: http://www.flickr.com/photos/aperture64/2739236380/
Last edited by summicron1; 09-26-2012 at 10:30 PM. Click to view previous post history.