Hey Adam, I've never done a double blind listening test either, but if any audio company wants to fly me to their research facility (or the Audioholics demo room) for one, I'm game.
I have done some bit rate testing on my own. Rip the same sample at different bit rates, and then write the samples as wav's to a cd, along with the original wav. If you put a bunch of them on a cd in a random order, and wait until you forget the order to listen to them, it can at least give you a feel for it.