The Lind adapter (above) and the equivalent from Kensington (http://www.kensington.com/html/2089.html) both look good. I've been trying to decide between them myself.

Both devices support both Empower adapters like on BA and other airlines and cigarette lighter adapters like on AA and in most cars.

I'm not sure if the Kensington can actually charge the battery, though, like Jet'Dillo says the Lind does. You might try searching through the TravelTech forum and see what you find there (and maybe report back what you find for selfish people like me?).