I saw a site today that has a 7 watt 12 volt fluorescent bulb that they claim produces the light of a 30 watt incandescent. If that's true, with an appropriate reflector it would make a great headlight, not so much for seeing the road but for being seen by other vehicles. That's almost as bright as a conventional car headlight. They claim 50 lumens per watt, which is better than even LED's.

The drawbacks I see: it's not rated for use below 32 degrees F, and I would wonder whether it could stand up to vibration.

Here's the link: https://store.solar-electric.com/sol12voldcli1.html

Your thoughts?

Actually, with the correct optic lens, it can project a pretty good beam. The only thing is the humongous glass tube has a lot of inertia and the mount is really fragile.

Yeah, LEDs are still far more durable, but only worth it if you're using Luxeon IIIs or Vs.