I love the redoubtable Canonet. I have a few, and I agree that I have yet to see one in which the seals do not need to be replaced. The Canonets are durable cameras with a good set of basic features. They are among one of the best deals in rangefinders when you compare price to quality. They also are one of the easiest rangefinders to focus (at least in models I have tried) as the images in the viewfinder are quite distinct.
Although the Canonets do use a mercury battery, which can be substituted with an alkaline or zinc/air replacement, they do not require it for their functions other than the built in meter. So no battery, no problem. I can't say the same for my Olympus XA and Minox 35, both of which will not operate without batteries.
I have an Olympus XA and Minox 35 which are nice pocketable cameras. Neither, however, is going to give you the functionality or flexibility of a Canonet, and both are most likely going to cost more than the Canonet; not to mention they are not near as durable as the Canonet (how many have had the film advance lever break on a Minox 35?).