Oh damn, I ordered 2 and now I wish I'd ordered more. I didn't realize the limit was that high.
As for things selling out... I'm now wondering if Hasbro is ordering smaller quantities. The last few sets of preorders DO seem to be selling out. The Landspeeder, Carson Teva, Asajj Ventress, Dengar, Kallus, Crosshair, and Bantha are all also marked as sold out. That's pretty unusual I think and you can still preorder almost all the older things.