This looks very interesting - headlamp can be fixed to helmet, 20 hours of light from a full charge, solar powered charger weighing 2 pounds.

Recommended at Cool Tools here:

Available at,portable_led.htm

Product info:
3 LED light with detachable 1/2 watt solar panel. Light is 2.3 x 2.9 x 1.4 with 3.6 VDC @ 700 mAH nickel-metal hydride battery, automatic photocell for dusk to dawn operation, on/off switch with gold plated contacts. Solar panel is 2.7 x 4.7 x .5, non-glass covered mono-crystalline cells with clear epoxy bonded to fiberglass backing, 5.6 volts, 100 mA with 3 foot cord. 3 hours of full sun charging provides 10 hours of light. 1 year warranty.
EL7 2 lbs $45 Special $29