Beechcraft Staggerwing had such in its version two. Ailerons on top wing, flaps on underwing, since got trouble with both flaps and ailerons together on underwing. I hvae such a RC model made with ailerons on top wing, but havent tried flying it yet.
Ailerons are easier to add to the bottom wing, you can just use a single servo in the body that way, as opposed to two on the top. My SE5 flies OK with ailerons but it didn’t make a huge difference. I would leave it 3ch if I was contemplating it again.
