Got a 70 Rogue with decent gear? Try the Mana Tombs in Terrokar Forest (The Mana-Tombs are a wing of the Auchindoun instance. It is accessed due north from the Ring of Observance.)
Zuggy, of Zug Gaming, has a video showing you just how to do this. He says that a Rogue can generate from 100 to 400 gold per hour, depending on your server, the economy at the moment, and your skills at clearing the mobs.
Your targets are the two chest that spawn at random places in the instance. It also helps if you have a combat build, but that might not be necessary.
Check out his page for the video. Mana Tomb Stealth Farming
And check out Zuggy’s Gold Mastery Guide for more killer gold making tips.