The old Regionals (SWRFI, etc) are dead.
Paul,
I know the question was about vendors, but all of the old Regionals aren't dead yet. There were over 500 planes at SERFI this past weekend, and while there weren't any vendors, I assure you a good time was had by all.
I've never been to Copperstate but it sounds like it's on a level with Sun N Fun as far as vendors go.
My $.02 worth