There is a member here, username is clairegoad, who lives on the west coast of in Florida. She has often posted about a very strong, active poly community in Tampa: http://www.polytampa.com/
She also mentioned that there is a poly-kink crossover group in Florida called "Bound to Love," which meets regularly, and they are on FetLife: https://fetlife.com/groups/13933
Hope this is helpful!
Quick update... PolyTampa is still active (meeting tonight at the TGIFridays across from University Mall... if anyone wants to join us.)
Bound to Love is no longer meeting... The influx of munches and kink events (i.e. FetCirtuit, The Web and several local dungeons.) meant the purpose of the group was filled in other places.
Message me (here or on FetLife) if you want details of when/where events are held.