There is/was a small commercial grower in Winter Haven, I believe. They were selling at the St. Pete Saturday Morning Market a few years ago and I spoke to them for a bit. They were near a body of water and said they've been successful, no issues with temps, etc.
Here in Pinellas County, mango trees are everywhere. In our neighborhood near the bay (Old Northeast) just about every block has last least one. Some are giant and I'm sure are easily 25+ years old. Our winters are warmer than Tampa but you'll find trees over there as well.