Spinnaker,
I started nighttime winter riding last year and had a Planet Bike light that used AA batteries. Nice light, but not much light. I then started following the forum mtbr.lighting and found a great idea. I purchase a LED flashlight from Dealextreme that uses 2 AA batteries (I used rechargeables). That thing cost $25 and puts out an amazing amount of light. I just use a heavy duty rubber band looped through my helmet to hold it on top. Since it's helmet mounted, I can direct the light wherever I need it. I ride back roads with no street lights and that little light makes it like daytime. The bonus is that I can use the light around the house or for other things, plus it's dirt cheap for the amount of light you get.
Not really what you spec'd, but a quick/cheap way to go