Oh, I almost forgot: I also made a 12V flasher circuit for my roomie's bike. It has a single flash output, and an input for a brake switch. It's a bit simpler than the one I made for my bike. If I had to do it over again (again), I'd probably use a CMOS timer and a MOSFET for switching (to use less power), but this one's not too greedy.
Stay lit,
JAB