It would never work. The banana's would be more expensive to no-one would buy them. The people working in the Banana green house would have to be paid more then the banana growers in other countries, making everything more expensive.
As for being better for the environment, it'll be about the same. The amount of heat needed i think would be more, the ships that normally carry these bananas will still be going, and so will the lorries transporting the bananas. So overall, no.
And anyway, how would the bananas trees get over here, they dont have seeds to make trees.