While checking out the World of Warcraft forums, we managed to find a very interesting thread about the Netherdrake. Nostro of Eitrigg asked for info on how they might be able to get a netherdrake flying mount.

He went on by saying that he heard a rumor that said that the "top rated players will be able to receive purchase an armored Netherdrake mount." And that if this rumor is indeed true, he thinks it's unfair to those who do not fancy arena matches (which includes him).

So with that, a clarification is needed. It was a good thing that WoW forums' Drysc was on hand to answer the question and provide some needed info. Here's what he had to say about that:

Well anyway, the armored Netherdrake will be available through the arenas as a reward, and a Netherdrake that has a distinctly different appearance from the armored Netherdrake will be available through a quest line which has not yet been implemented. It's likely that it will be implemented with the next major content patch.

They're both epic flying mounts, just to clear up any confusion on their speed.