I have added a vendor group to the user membership list. I have seen other forums do the same thing and it seems helpful so people know they are talking with a person in the business not just someone trying to pass junk etc... No differences in permissions other than they will have the ability to create events in the commercial and job posting forums.

There are around 20 vendors currently listed
http://www.professorpaddle.com/forum/members.asp?SF=&GID=0&SO=GP&PN=7

Get your industry beta from these guys!!!