patch 2.3, now here's a bit more. In response to a poster who was complaining that the Horde will soon have access to an Alliance mount (the Ram, via Brewfest quests) while the Alliance doesn't have access to any sort of raptor or wolf or anything, Bornakk says:
While it would be available for both factions, we could also put in an epic flying mount that is purchasable for those who are exalted with the Cenarion Expedition. It would be very expensive, but it would be a sign of an accomplishment for people who go the extra mile and purchase one.What sort of flying mount could it be, we wonder? Hippogryphs? I would have guessed nether rays if the Sha'tari Skyguard hadn't already snagged those. Does the Cenarion Expedition have a secret cache of flying cows they're not telling anyone about? The questions continue to pile upon mysteries already heaped upon enigmas!
Hmmm... this does sound like a good idea, how about we do this in patch 2.3?
Update: Riddle unraveled! Apparently, it is a Hippogryph, and at the normal 280% speed. Thanks Icho, for asking the question on the forums and finding out for us! I had been hoping for an enormous Zangarmarsh firefly after reading some of the comments -- that would be classy! But alas, it is not meant to be.