Get the Great Planes 60 size Cub and then order a Super Cub cowling from fiberglass Specialties. Get the Float kit when you order the plane from Great Planes. There both on Tower Hobbies. The Cub has a 90" wingspan and the floats are 41" long. A 91 4-stoke will fit inside the cowling except for a cut out you have to make anyway at the bottom of the cowling's front for air. I'm building one now for the same reason. Makes a great Bush Plane.

Gibbs