When I was working on farming rep for the goblin factions, I made a huge amount of gold in Dire Maul. First, there are the librams, which can easily sell for 200g+.

If you have are a rogue, you can pickpocket your way through the ogres for the heavy junkboxes and it's easy to find someone working on Insane to pay 10-15g each for those.

Finally, I had my engineering toon parked to drop a mailbox. I ended up leaving that character there for weeks to check for the rare spawns in the DM arena. The Orb of Deception seems to drop at a higher rate than wowhead lists and sells for 3000g or more. The deposit is so low, if people undercut by a lot, I just kept listing at 3000g and eventually sold all four I had.

Edit: Link to Mageshadow's post about the Gordok Ogre Suit.