I was searching for a way to increase the amount of traders in the world (either through mods or world generation parameters), as I felt they were too few and far between IMO. Your idea about relocating them to your base at a sort of caravan bazaar sounds awesome however!
It will create a goal in and of itself to gather all kinds of merchants and enable a real economy. Or maybe if NPC settlements are ever implemented, trade routes could be introduced. I'm just letting my mind wander about the possibilities.