I have an idea! How about the old Jemco Mustang (two sizes) and the Jemco P-39? Also the 80 inch Dynaflite Spitfire. Those were great designs that built very light and flew great. They turn up on ebay, but they get good prices. I have not seen short kits for any of them. If you got Parkflyer to make the canopies I think you'd get some business. Might need to come up with a canopy mold for them, then let Parkflyer pull the canopies.
One more thought...the 80s were awhile ago, ya know. Might be some old Great Planes designs and others that people miss.
Jim