I checked in at my local comic shoip, and the guys there told me that Diamond Previews will have the Darth Vader and Yoda mini-busts available for pre-order in the next issue. Good news if you get these through your comic shop.
Mosnab, as many in this thread will tell you, I'm a big advocate of ordering these through your local comic shop. If you can hook up with a good comic shop you can get these for less than they're listed at SWS, BBTS or EE. And you won't pay shipping either. That being said, if you don't have the benefit of a good comic shop in your area, I would recommend any of the three e-tailers that I mentioned.