>>> Torqeedo

Torqeedo is a German company (products also available here in the U.S.) which is making a line of high end, highly efficient electric "outboard motors". I haven’t found anybody with direct experience with them yet, but their web site gives lots of detailed information, including technical details on power output, usage and the like.

They have one small model that is self-contained and folds up… battery is included in the "head" so that you have an entire motive power source for your dinghy or whatever in a portable unit.