I decided to check and according to Amazon/Dvdaf The Dead are Alive was released in July 2010,I received mine in October 2010 (I remember it took me a while to purchase it and I finally ordered it in September from Axel),in March 2011 I reported the oop listing on the CR site and then it certainly took more than half a year before it was finally no longer available at webshops.
I can imagine it being hard to find in "brick and mortar stores" in the USA but I'm surprised you weren't able to find it online,didn't Amazon carry it?