I've had a little experience with portable stage lighting for storytelling. We were considering using clamp-on lamps with compact fluorescent bulbs, in order to avoid generating a lot of heat, but we realized that such bulbs are not suitable for devices that need to stand up to a lot of handling and might get dropped. Broken incandescent bulbs are fairly benign except for sharp edges, but broken CFs can release mercury, and one is supposed to take special steps to clean up the mess.

We used incandescent bulbs for a while, but the only place we could clip them was to a waist-high table in front of the teller, and the shadows were unflattering. (We don't need amplification, so we don't have any microphone stands.) We've now reverted to tolerating the relative darkness, with most of the room lights turned off. Since our house rule is that we tell stories but don't read them, darkness is not a critical problem.

When the prices of LED-based lamps decline enough, those might be the best option. I can even imagine being able to run them for a couple of hours using rechargeable batteries rather than plug-in cords.