A co-worker wit esophogeal cancer had surgery that made the distance from his mouth to his stomach quite small, and can no longer tolerate carbonated anything. Twisted Tea works for him.
I don't think UN-carbonated beer tastes bad to begin with. The carb certainly changes the flavor and texture, but without it I've never found a bad one. You will likely need to have a sweeter brew to give it the mouthfeel you are after though.