Burning Crusade Vanity Pets
This is one way to make WoW gold I%26#8217;m kicking myself for not thinking of sooner. In fact, I%26#8217;d thought of it then forgot about and then was reminded by someone else about it later (did you follow that?).
With the release of the two new races in Burning Crusade also comes the release of a new vendor-sold pet - the Blood Elf Dragonhawk Hatchling. This vanity pet goes for a base price of 50 silver from Jilanne (43,70) in Fairbreeze Village in Eversong Woods.
Horde owners of the Burning Crusade expansion can make a ton of gold selling these to other Horde players without the expansion. The real gold, however, comes from selling to Alliance players (who have no way to get this pet otherwise) via the goblin auction houses.
Also, with Burning Crusade comes a new friend %26#8230; Dealer Rashaad . This guy sells all kinds of pets which were previously unavailable cross-faction or only available as a drop (like my good friend the siamese cat). Because these pets are priced fairly high I haven%26#8217;t bothered to try to relist these yet; if you have please post your experiences in the comments.
Note: Because the competition to sell these pets is already likely fierce on your server, you may try to sell some of the other has-been pets at lower costs for the buyer who can%26#8217;t afford a Hatchling but get all fired up about having a cross-faction pet. A few of the other vendor-sold pets include Snakes and Cockroaches (Horde), Cats and Owls (Alliance) and parrots (Booty Bay).
I recommend reading Valkor%26#8217;s Gold-Making Guide to learn more about utilizing advanced auction house tactics to pwn your competition. It%26#8217;s got 108-pages of continually-updated tips, 100% legal strategies and reference lists that will take you to the next level.