Yes there are different varieties, if you Google dwarf banana's you'll see them..

There are many types of small fruiting bananas as Christine mentioned; what you saw might have been a Super Dwarf Cavendish (the height description seems to fit the bill) although there are even smaller varieties such as Little Prince. You're in luck being in Florida as there are tons of nurseries with different banana types that could be better suited to your preferences, and plenty that only get to 5-6' before fruiting. Offhand the regular Dwarf Cavendish (that is, the Non-Super Dwarf) gets to 6-8' and usually produces big bunches, and the Raja Puri (5-6', resists wind well and is more cold-tolerant), Dwarf Ladyfinger (more of a dessert-type banana), and Dwarf Orinoco (extremely common, can be baked or fried as a cooking banana or be allowed to ripen to sweeter tastes and eaten out of hand ,versatile).

What I'll do is link The International Banana Society's Website, which was very helpful to me when I first discovered my love/addiction to growing bananas a few years go. It's set up in a forum format similar to Gardenweb so navigation should be easy for you, and there is a huge wealth of cultivar and cultivation information in the various threads, along with Wiki page on different types of bananas. The members also tend to be very helpful, and I know quite a few that live in Florida that trade banana plants among themselves or are willing to give to pickups. Enjoy!