I don't know what they have currently, but a few years ago I picked up a couple of cute ones at a Claire's. So you might check there, or some of the other "young" accessory places. They seem to have wood stuff each time summer rolls around...
I love wood bangles. I have five or six that I stack together when the weather gets warm.
__________________
"Good taste shouldn't have to cost anything extra." - Mickey Drexler
Try World Market. I went there recently and bought a couple. They had these really large dark green, maroon, brown, navy, etc. large bangles. I think price was like $10.