Very strange. When I add Alien to my queue, the format defaults to DVD. When I switch it to BD, it goes into the "Saved" section of my queue with unknown availability.
Surely all of their copies of Alien on BD haven't been damaged in the mail or lost, but I can't think of any reason why they don't have it. I'm sure demand has spiked with Prometheus on the way. Alien is a great flick, IMHO, and the BD transfer is really good.