RE: 1/2a pylon racing kits?
There used to be a model called the QT. It was powered by a Cox .049 with tank extension. No throttle control, obviously, and no TD's allowed, just rudder and elevator. Everything was square and made from stock balsa so the wing was limited to 36". I think NE Sailplane makes on the call the Cutie but believe it's electric. Could be made into a 1/2 A nitro to go fast and turn left. Design has also been modernized with rounded tips and such but is still a parsol type.