Incredible craftsmanship, both on this and your MP3 player. This USB case is so well done, I can't even figure out how you made it. I can understand machining the inside locking barrel but I don't see how the case could be CNC'd. Did you use traditional hand engraving tools?
Excellent work! And congratulations on coming up with such an original design.
$40 would be pretty awesome. If you're going to get them produced rather then hand made by you, maybe you could talk to ThinkGeek.com they sell some awesome nerd stuff and love to find new things to distribute.