I know I could have gone the halogen route, but I don't find it nearly as impressive as a high power LED array. Also, the runtime and dependability wouldn't be nearly as good. A 3w LED is quite impressive to see and the bike lights that come equipped with them are expensive for no good reason. I'm anxious to see how bright 6w (or even 12w) worth of LED light can get.
Does anyone remember those hand guard type things that are popular on dirt bikes? Do they make them for mountain bikes? If so, I think if I had to use 12 LEDs, they would be a good option for mounting them since my shift/brake cables interfere with handlebar mounted lights. I figure six on each side should be plenty to light up the night and still give a good five hours of runtime.
I'll also have to come up with a current regulator circuit to drive the leds at about 32mA from the battery pack. I'm pretty sure I can throw together a MOSFET based circuit that will do the job. For testing purposes, I'll assemble the LEDs and drive them with a 12v source and limiting resistor. This is too wasteful to use on a bike, but I'll have a good idea of what the LEDs are capable of and will post pics.
Still awaiting parts...