Im actually not wanting to play this mod now, for my starter fortress is over bitimous coal, which means I cant mine anywhere because I keep getting lung desiese, and with no doctor (5-10 mins into game) I reckon my dwarfs are as good as dead - The gas is overpowered, and doesnt help starter fortress's.
Y'know, there are plenty of other rocks you could try digging through.
Can't really think of anything more appropriate than "broker", that doesn't infringe on another position, Deon. Unless you wanted to go with something flowery like "treasure expert", but that seems to be overlapping with the Dungeon guy.
Come to think of it, how come it isn't the Dungeon Master's job to value the treasure? S/He's always pondering the stuff.