#1 - Dec. 1, 2012, 1:47 a.m.
If you look a little ways down the page, you'll find that there's a thread on this exact issue. :P That said, if all goes well, there will be a hotfix issued before Tuesday and you'll hopefully get your mount with it.
Any word on Tournament mounts? I earned them a while ago on horde side and then changed my faction prior to 5.0. I now have a few AT mounts on my horde, but not others. (Missing the ones like the skeletal warhorse, wolves, etc.)