Just curious what your reasoning is for the suggestions. Batteries are one more thing to keep an eye on and maintain/charge, a dynamo light is just there and works, no maintenance needed. Disc brakes vs rim brakes can be argued all day long, so I'll say that's a personal preference, but I'll switch to disc on my next commuter (no brake dust on the reflective tire sidewalls, better performance in rain and snow). I wouldn't want a fixed gear on a 20km commute, that's a whole other style of riding I don't think the OP is interested in based on the requirements in his post. Belt drive doesn't have a chain that needs lube, and a decent internally-geared hub can go a while before a rebuild.

A Civia Bryant came to mind as being close to the requirement's, unfortunately they stopped building them not long ago, but the idea is there.