I thought the links page would be the most helpful with links to almost all AIPAD members all over the world, including SF and NYC. Maybe Davids friend should contact AIPAD and find out when and where their conventions are. That way he can see a whole group of dealers in one location and talk with them.
They have one in NYC at the Hilton every Feb. I have been to several and it is well worth the effort.
I met Ben and his lovely wife, at a AIPAD convention in NYC several years ago.