[marknorton]

My understanding is that cosmetic changes to a product do not affect the warranty but it's possible to think of a heavy handed approach causing damage, for example, using paint stripper to remove any adhesive remnants will wreck the camera.

I haven't seen any reports of Leica refusing to honour any warranty claims in a re-covered camera; of course, you cannot expect them to replace any cover if the camera does go in for service, I expect they will just replace it with the standard cover. The leathers stretch and tear when you remove them.

Some simple repairs, such as rangefinder adjustment would not require the camera cover to be removed anyway.