I hope you won't mind some info from a book light manufacturer. I'm from ASF Lightware Solutions (
www.readinglight.com) and the
Beam N Read Hands Free Light noted by Brookstone (Thank you) is our product. What makes it different, is that instead of clipping to a book, it's worn around the neck and shines light from the chest. So there's no issues about attaching to a device or extra weight on a reader. We have 3 LED and 6 LED models with the LEDs in a horizontal row for a wider light. The 3 LED model easily covers 2 pages of a hardcover book so it's more than sufficient for an eBook reader. Standard alkaline AA batteries (4) last for 120 hours in the 3 LED model (BNR LED 3). MSRP is US$19.95 including a set of batteries. Because it's worn around the neck, it's also useful for many other tasks where it's helpful to have hands free such as knitting and for changing diapers at night (I've used it for this a lot). Also as a travel light, power failure light, and walking in the dark. Since I'm from the manufacturer, I'll leave it at the above technical info. Two independent product reviews did specifically address its use with ebook readers:
Gadling.com, a major travel website, and
GearDiary.com. Excerpts and links to more than a dozen
product reviews are on our website. And it is also available on
Amazon and a variety of other online and bricks and mortar stores.