I think it can be made, by simply cooking the pureed banana with sugar until it's perfectly smooth, then cook on a silpat at 250 degrees for an hour and a half or so. I've done this with many fruits, and most work well. The ones that contain that protien eating enzyme, such as kiwi, pineapple, papaya, and blueberry, for some reason, are the ones that don't come out chewy. They just sort of crumble. My guess is that banana will come out great!
By the way, what is the name of that enzyme?