Do any of you guys play EvE Online? When I discovered DF, I immediately thought how spectacularly rad it would be to have the dwarven economy in EvE. Mining ore into a would earn dwarfbucks, as would hauling it to station, refining it at your level of ability and processing it into goods. Everyone could be credited for their individual contributions, and then could use that "credit" to pull finished gear out of the shared inventory. Nobody could rip your group off, since their withdrawals would never exceed their contributions, and you could weight votes for decisions (war declarations, establishment of facilities, etc.) based on the portion of the overall value for which each member is responsible. It would be the perfect communist democracy, and would reward both the individual and the group for acting in everyone's best interests.
I hold EvE as the "best we've got" example of MMOs, and might reactivate good old Reggie Stoneloader one of these days. The thing that always chased me away was that you could farm NPCs and get rich without actually producing anything, then buy fancy combat gear and go kill miners with it (one of my favorite hobbies, but still...). If a battleship in space represented the infrastructure to build and equip it, rather than just the dedication to grind on harmless NPCs, I'd be paying every month to inhabit that world.