Now that I see there are cheap dynamo type lights that may be decent, I like the option of bolting lights onto the bike. Oddly, they seem moderately theft-proof. Even here in a bike-theft prone city, people don't steal lights that are bolted on. Has anyone powered a light intended for a dynamo (A/C) with a battery (DC)? 5V might just do the trick.

Of course, I could try it, and I might. I will report back.