This is the light I use with my 505:
http://www.amazon.com/gp/product/B001GS6LDA
It's big -- it's basically a laptop keyboard light with an AA battery pack (and you can also hook it into any USB port) -- but it is an awesome light. Thanks to its five spread-out LEDs, I've had zero glare, although admittedly this is on a 505, which doesn't have the 600's glare problems. I'm planning to build a little clip for it that will slip into my M-Edge Executive cover's booklight slot, so that I can hook the light onto the book cover and have its battery pack, which does have some weight to it, at the other end of a USB cable. It also serves as a light for my netbook and I'm thinking it may make a good car map light, too.