I like your idea..
I have loved that idea since the day I saw a picture of the yellow one in Hawaii (owner?). But, then I ran into a guy at our airport that had just finished a Thatcher CX4. It uses the VW engine(Im thinking it needs a C75 or C80) and has similar RV lines to it. Sweet little single place all metal open cockpit..not to stray from RV's, and I will never sell my -4. But I keep an eye open for an abandoned CX-4project.