I use a Wheat Lite head (4 Volt bulb) or a Nite Lite head (6 volt bulb), and build the battery packs (6 volt battery charged up to 8 volts) myself. They last ALL night, and are bright.
It's very simple construction, I use a rechargeable gel battery, and a Radio Shack rotary switch with diodes soldered between each post on the switch. This drops the voltage about 1 volt per position on the switch and allows you to dim the light correspondingly.
Clear as mud?
Anyhow, it's a good rechargeable light for relatively cheap.