Thing is a lot of Mac users have held off upgrading until the release of the MacPro. Hence they are moving a LOT of these machines. That they are also wicked fast, and extremely stable has helped too.

This also means that they are rather in short supply.

I can understand your frustration though. In my case however, I went in to VR Tech to pick up my .Mac renewal box and ended up walking out with a MacPro.... Zero wait time...