Ok! So you have about 1 week to do this, since WOTLK will be out then, and im guessing the price will go down then since blue gems will surely be better!
This is simple, and I will keep it short!
Say in trade chat "Buying all sorts of uncut epic gems, 50g each! Turn in your Badge of Justice before its to late!"
Normally you will get alot of whispers, and now buy all sorts of gems! (Most popular on my server is Lionseye, Crimson Spinel and Pyrestone
Find a jewelcrafter, make perhaps 50 different sort of gems (Purchased for 2500g), put these on AH for whereabout 140g.
And over the night, or perhaps 2 nights, they will all be sold, and you will then get 7000g, with a profit off 4500 gold!
This was no copy pasta, and I did not find any other guides with this one, and if there is one, I couldnt care less.
I hope you earn some money before WOTLK! GL&HF!