Species bananas that would do well include:

musa basjoo
musa sikkimensis
musa mannii
musella lasiocarpa
musa 'Royal Purple'
musa velutina
musa itinerans
musa balbisiana

Fruiting varieties (all of these need a little extra protection in a zone 7a winter):

Orinoco
Raja Puri
Brazilian
Ice Cream
Goldfinger

This is just off the top of my head...there are many others if you take the time and research it on the web.

Its not going to happen. :-(

Zone 7 winters are too cold to grow nanners outside. They will freeze down to the grown if unprotected.

I know a person that builds a small greenhouse around his nanners and removes it in the spring.

I myself, dig mine up every year and put them in pots and move them into the greenhouse.

I am thinking of the mini greenhouse idea around one, next year, just to see how hard of work it can be.

Now if you are looking to grow the plant in the ground and let it freeze back to the ground in the winter, aslong as you dont freeze the corn, it will grow pups again in the spring, but you will likely never have a stalk of nice yellow nanners hanging from your tree.

{{gwi:414926}}
Here is a bunch of nanners that I grew one season. Not a big stack but a few.

Musa Basjoo will be just fine outside in 7b without special protection... anything else will surely be killed by the cold if you leave it outside over the winter.

If you don't have access to mini-greenhouses and can't dig it up in the winter, Basjoo is your best bet.

All of the first list of bananas that I mentioned can and do survive in zone 7 winters. In a true zone 7a winter, it would be wise to add a few inches of mulch for protection from the cold. Also, all of the bananas mentioned will lose their pseudostems (without extreme protection) in the winter. They come back from the corms in the spring. There is no digging necessary!