Zeiss Ikon is awesome, fairly light, but no smaller than a Leica.

Bessa R2M, R3M, R4M are great too, maybe a little lighter than a Ikon, and a lot cheaper.

If you don't mind finders and range finders being separate, check out Bessa T and Leica IIIf. The Leica is tiny but heavier than the Bessa T. The Bessa T is still small, and has modern conveniences like film loading, meter, and the range finder was clearer my Leica IIIf.

If you want really tiny, there is the Contax T. It's AE only if I recall right, but it's very small and very light.