I made my epic land mount gold by selling level 60 enchanting mats -- they sell for a ton, especially illusion dust and greater eternal essences. If you run BRD/LBRS/Scholo from level 50-58 and disenchant everything you'll probably end up with 1k-2k gold easy from disenchants.

The level 70 regular flying mounts came a few days after I hit level 70. I saved the quests in Netherstorm and Shadowmoon valley to get gold rather than xp.