Bill,
As I recall, the Cincinnati, OH club, Queen City U-Controllers, ran this event for awhile. The planes were all scaled to a 36" span. Most of the ones I saw were one offs from the builder's own drawings.
The AMA Plans Service has a Keith-Rider R-5 Marcoux - Bromberg Jackrabbit, plan # 21874. I'm sure there are others as well. The neat thing is that all of the plans have been scanned so the plans guy can factor the plane of your dreams to 36". All you might have to do is figure some of the wood sizes.
Bob
P.S. Late thought: The guy that runs the Cleveland Model plans company will also scale to any size. Cleveland has most of the Golden Age race planes. Again, you would have to work out some of the wood sizes, but all the shapes are there.