Waaaay back when, I had written some posts about faction specific recipes, notably the Kaldorei Spider Kabob recipe quest. I just wanted to inform you that those hard to obtain faction-specific recipes are essentially GONE.
Tasty Lion Steak from a level 30 Alliance quest and the Kaldorei Spider Kabob recipe from a level 1 Night Elf quest have been deemed obsolete, and can no longer be gotten. However, the Moongraze Tenderloin recipe, from a level 4 Draenai quest, can still be gotten, it would just take more time to level a throw-away toon to level 4.
However, if you do happen to have the Spider Kabob or Tasty Lion recipe sitting around in your bank, they will sell very well on the AH. I just recently sold a Tasty recipe for 1,500 gold, with another one priced at 22k-25k to make it look more attractive. And on Wowhead, a commenter said that he sold it for 10k gold, with no advertising.
On Horde side, my main items for grabbing off the AH and selling on Alliance side had their drop rate jacked wayyy up, making it very hard to sell them reliably for a decent amount of gold. Yup, Elixir of Giant Growth and Savory Deviate Delight would probably not be worth bringing over to Ally side anymore if you're on a high-pop server, since there will be so many other Allies leveling up alts in the Barrens now. On a low-pop PvP server though, there's not as much competition, so if you bring them over, have one alt post a few at lower price, and have another alt post them at a much higher price, and they'll sell....eventually.
On a different note, 2 pets are no longer available post-Shattering. The Smolderweb Hatchling from the quest En-Ay-Es-Tee-Why(Nasty), and the Worg Pup from Kibler's Exotic Pets can no longer be obtained. This doesn't have anything to do with making gold, since the pets were BOP, but for all pet collectors out there, it's kind of annoying.