Actually the time-based dimmer idea works for me, too. You see, I have a Subaru with daytime running lights, but I just leave the light switch on all the time. The car shuts off the headlights if the key is not in the ignition, so I never have to worry about turning on or off my headlights.

My Empeg IS hooked up to my dimmer wire, but since my lights are always on, I adjust my dimmer manually.