This isnt for those people who just sit with 5g in their bank and want to make 20000 gold in one day!
But it could help, if you want to try. Recently tried this, and it works perfectly, and GM helped me do it, although he knew nothing about it.
On my main, i had around 1150 gold, which i had farmed/traded/etc. So here i came up with a plan one day, and i have my friend's account which helped me do it.
What I did was,
1. Made an alt on friend's account, Put up a grey item on for 500g, and then bought it out on my main.
2. Then i went and opened up WoW on two different PCs and traded away the rest of the money, to the alt on my friends account.
3. I relogged onto my friend's alt, traded the money to MY alt, and then traded over that money also to the main on my friends account.
Now with the gold transferred, i made sure that blizzard will NEVER find out where exactly my gold went through whatever investigations. Although these are not necessary, since i found out that blizzard dont actually track down gold, and just simply give in to the figure that you dish out. But anyways, this is what i did.
4. I then traded the gold back to my main, with the main on my friend's account.
5. I then made 10 auctions of 100g each, for silly items, on my friend's MAIN character and bought them out from my main.
6. I then deleted the alt, recreated it, deleted it again, and created it again for the last time.
7. I traded the money back to MY main from my friend's main, and then traded it back to the alt in my friend's account.
I then logged into my account with the other computer, and i deleted all the characters but did not touch any gear. I then went online and changed the account's password as well.
Then i went over to my computer, logged into WoW site, used the forgot password feature, to retrieve a new password, logged in, created a New character and Ticketed a GM. Stating that my account has been hacked, and i used antivirus thingy, and a Trojan.Backdoor virus was found and deleted. I dont know what happened to my character, gear and gold, but i had around 3k gold on it as i last remember.
My account then was suspended, and i was mailed by Blizzard. I immedaitely responded through a Webform and i gave then my cd-key etc and proved my ownership. In a week's time, my character was restored, and after one more week of investigation, i was mailed my blizzard to ticket a GM for reimbursement. I did so, a GM mailed me 3k gold as my reimbursement. Which again goes to show that all the investigation they do, is to really check whether you were hacked or not.
I then rinsed and repeated the same procedure in my friend's account. Transferring the money from his account to mine this time, he already had 1.5k gold, and along with mine, he had 4.5k on him. I again used the same procedure and quoted loss of 7k gold this time, and again, i was Mailed the 7k gold on my friend's account.
The whole process took some time, but is a FAIL-SAFE method, wherein a GM HIMSELF will come and give you the money, and all you have to do is play with blizzard's customer appeasement policy.
If this works for you, or if you feel its something new. Reps would be appreciated!