We attended the Florida RV Show at the fairgrounds in Tampa a few years ago and it was nice. The show was very large with a lot of differant manufacturers and rigs present. We went for one day but could have easily spent 2 full days seeing all the rigs and displays. This was before the recession so it may be smaller now but it is a popular show.
http://www.frvta.org/florida_rv_super_show.asp