If your booklight is one that you can clip to the bottom, right corner that may reduce some of the effective bulk and weight for you. Mine does, and I find it actually makes it easier to hold the Reader, since it kinda gives it a "base."
I've been very pleased with the CCFL light I've gotten, but there are a lot to choose from. There are about a dozen threads on the topic in the
Reader Accessories subforum, if you're looking to investigate them.
