The question of the Betrayal at Calth not being available, or at least having a very unknown lifespan has come up countless times. While in general we don't know these things, a solid source has come forward to help out. While I mentioned this in the comment sections to concerned readers, it is worth an article to help take a little of the panic out.
While this is still a rumor, its from a very good source, reporting on what he has seen and/or been told. These numbers are only a few days old.
via anonymous sources on Faeit 212
GW US has 4,500 Betrayal at Calth in warehouse and more in England. No numbers on England qty though.