One of the Minox 35 is pretty easy to carry around all day. Even though it looks crappy it has a fine lens and is very pretty sturdy. It's guesstimate focusing though, no real rangefinder. But with 35mm focal langth and DOF-markings on the lens focusing is not that much of a problem after some practice.
Also the famous Olympus XA comes to mind which actually has a rangefinder.
Talking about Yashica you my have had the
Yashica Half 14 in mind which is the speed "monster" of half frames. But I think it is very very rare, collectors item and such. You would have to sell your Leica gear to get one of these - Just kidding. But for a user the Yashica Half 17 might be the more reasonable choice.
Check out the
Sub Club Camera List if you are looking for a camera for your pocket.