On my last trip to Florida to visit family and friends and to surf, I stopped at the Longboard House in Indialantic, Florida. They just opened up the Paddleboard House. It is located just south of their main facility at the corner of 192 and AIA.
They have a fantastic selection of SUP boards, paddles and equipment. Naish, Starboard, Surftech, Werner, just to name a few.
Ryan is the General Manager and a great guy to get to know if you what to SUP in central Florida. They also have a good selection of rentals and do demos and lessons.