In 20-30 years, if batteries are cheap and light, this would be the type of application where electric power might shine. Put three 10kw electric motors pusher style in each top wing, each turning a 36" prop. For storage or transport on a trailer, leave the wings alone and hinge the empennage to one side or up-and-over. Pull three pins to allow all the wheels to castor so it can be pushed wherever it needs to go. Very low disk loading allows for good prop efficiency, and failure of one engine doesn't create crazy amounts of asymmetric thrust.I wonder if putting the props on airfoil-shaped masts projecting left and right from the fuselage above the rear wing might be more effective? You could have a removable, self-contained unit of engine, mount, and a T-shaped structure with the props on the ends of the T. The wing installation would then be much simpler and folding or removable wings could be an option. Better yet, put one large prop on a single vertical mast and give it a T-tail in the propeller stream rigged to counteract the nose-down tendency with power like many amphibians.