I wasn't able to find any other threads mentioning this, but for those of us who are interested in doing some light painting and have been looking for a cheap off-the-shelf solution, you may want to consider this:
I bought one while they were on sale at $35, and used a 25% off coupon I found in my motorcyclist magazine bringing my final cost down to $27.
I've been using this light for a month. The flashlight has been reliable and durable. While I'm all for DIY rigs and solutions, I don't think it is possible to build this light for this cost. It comes with a built in lithium battery and a wall wart charger. The light has a high and low output mode, a hook and magnetic base on each end as well.
Here are some results: