Maybe this already exists and I just haven't seen it, but I think it would be cool if there were different character titles (like Master Wizard when you complete the Mage's Guild quest line, or Volunteer in Cyrodiil) that a player could place on their character that would basically advertise a crafter's service. If a player has a particular crafting title, another player would know they could approach them and barter for crafting.
Another idea would be to have town bulletin boards, like the crafting writ boards, where a crafter and/or players could post crafting services or items wanted.
Seems like better immersion than just yelling in zone chat.
Good idea, bad idea, not needed, pain in the ass?