Look for reproduction carbide lamps -- search for camping or mining type lamps, not bicycle, to get more hits. They don't even need to be working if you're handy and can modify them to use LEDs and rechargeable batteries.

Probably be an expensive mod, though. Even repro carbide lamps are expensive, lots of brass and glass.

You can probably even find a working carbide lamp, if you want to get really retro.