https://twitter.com/TheCrafticus/status/501930988692180994
So the Emerald Drake was revealed to be the 250 mount reward, but now that’s being changed to a Felfire Hawk, and the Emerald Drake is a reward for collecting a number of other dragons instead!
https://twitter.com/TheCrafticus/status/502166492419342337
So let’s have a look at how we get these mounts.
- Azure Drake: Drops from Malygos in Eye of Eternity 10 man. Unsure of how to solo him? I have a guide for you right here!
- Black Drake: Sartharion in 10-man Obsidian Sanctum. Guide to soloing this is in the same guide as Malygos.
- Blazing Drake: Madness of Deathwing (normal or heroic). Those of you dreading soloing Spine, see the above tweet. Changes are being made!
- Blue Drake: Malygos in Eye of Eternity again. Greedy dragon.
- Bronze Drake: The Culling of Stratholme from the Infinite Corruptor. It’s the timed run that awards the achievement The Culling of Time and is trivial to solo at 90.
- Onyxian Drake: Onyxia. Guide here!
- Purple Netherwing Drake: Get Netherwing reputation to exalted, then complete the quest Malfas the Purple Nethweing Drake, or buy from Drake Dealer Hurlunk for a mere 200 gold.
- Red Drake: Exalted with Wyrmrest Accord. Buy from Cielstrasza (atop Wyrmrest Temple in Dragonblight) for 2000 gold.
- Twilight Drake: Sartharion again. 3 drakes up again. This time? 25 man. Still trivial at 90!
So what are you waiting for? Go out and collect those drakes!
Panda Steve Types Stuff 
*throws away troll dice & looks for luckier ones*
Well, I’m only one off on the drakes and might slip in there and run crazy for a few days to see if I can get it to drop. I wondered why they sent it to me in Beta and said “you can’t use this one” after I took it out of the mailbox – silly Blizzard and their teases.