How about a mod crafter? Someone who takes rare and common materials to make upgrades for your weapons? Example: 7 Ebon Spider Legs and 25 planks of wood will get you an ebon bow grip (earth damage). This would be a really good gold sink, although it may ruin the arms trade. However, it would reduce the need to buy GW gold online and therefore reduce inflation. Maybe this could be added if buying the mods were dam expensive and hard to make, therefore making it more of 15k armor type of thing instead of a "let's go buy forty max fortitude mods from the crafter!" type of thing.
What do you all think? I actually promised a guildie I would post this for her, and my view on it varies from one spectrum to the other, so I'm not going to argue one way or another on it. I just want to see what you all think.