People on my sever are buying the Truegold CD for 100-150g a pop. Usually takes 1/2 mins advertising in trade. I never let on that my specialisation is Transmute mastery, however playing the averages you could offer to work for 200-300g and they keep all procs. This is a scam however, playing by word the CD only says 1 bar so you can probably get away with it were a GM involved.
However, how I like to play it, let them know my location (usually VoS AH abusing the weak). Don't let them party up etc etc they tend to QQ if in a party (Say your in a LFG que or w/e). Do the transmute for them for 100g and keep any x2, x3, x4 or x5 proc. I tend to sell the proc's to the player at 100g cheaper than the AH; As there probably trying to craft to make a fast buck, fact is your making a faster one.
With the 100g CD cost safe the proc usually gives 600g extra per bar. Playing the averages your in to make gold if you can't be bothered getting the mats together yourself while having a buyer usually for any proc's at hand.
I've been rather lucky with several x5 proc's and am making lots more gold than my elixer master alchemist.
Hope this helps you fellow lazy people make a fast buck.