Dave Jacoby always has a booth at the Derby. There usually a few vendors that buy and resell collectible cues there as well. If you want to compare a lot of different sticks, then The Super Billiard Expo will be a better choice.
I posted a video here and on the main page. I talk with or at least show everyone that was selling last year. It has been the same people for the last 4-5 years that I have been there.
Mark