There are numerous other methods of inflating prices and working the market as well with this dual character method. Keep in mind that some other methods of Auction House gold making will anger your fellow players if misused.
Another option is to sell your account to a company that buys and than resells game accounts but they are going to want to pay you a small fraction of what your account is actually worth on the open market.
Also, this expansion introduces some new features that will ramp up the already spectacular WoW gaming experience. Find out what you can do to prepare your account for World of Warcraft: Burning Crusade.
Most of all, you're risking the compromise of the entire game by buying gold from farmers that destroy the economy by overharvesting.
Remember all of the death runs? What about the trudging to booty bay from the top end of Azeroth when you had no flight paths? A readymade character will have the flight paths, and some gold to get you started.
By paying for a ready 70 toon you'll be able to log in and play the game at its highest level, experience Azeroth and the other worlds as they were meant to be experienced - no more death runs when at level 63 and trying to get through one area to another you've not yet explored.
The key is being able to build characters fast and there are programs designed by pro gaming teams that enable you to level a character in about 6-7 days and guide you every step of the way. Once you have a program like this you are set to go into the business of making money with world of warcraft.