You don't say which Gee Bee you're interested in. The Granville brothers designed many planes.

Model A (radial engine, biplane trainer side by side)
Model X (first sportster, inline engine)
Model B,C,D (sportsters, inline and radial engines)
Model E (sportster, radial, racer)
Model Y (senior sportster, radial engine, won more money than any other Gee Bee)
Model Z (radial engine, racer, National Air Races)
Model R1 (radial engine, racer, Thompson Trophy)
Model R2 (radial engine, racer, Bendix Trophy)
Model R1-R2 (long tail racer, combined R1,R2 parts, stretched fuselage, never raced)
Model Q.E.D. (radial engine, Distance time record)

There aren't many kits available but it depends on which plane you want to build. There are a lot of plans available if you're up to making your own kit though. Below are a couple of links for the D and E model in the size you're looking for.

http://www.soy.on.ca/geebeed.html

http://www.soy.on.ca/geebeee.html

I just received the plans for the model D from the AMA. They are the same plans used for the above kit. I also bought the plans for the model Y but this is a 1.20 size plane. I've been doing a lot of research on the Gee Bee's so let me know exactly what you're looking for and I might be able to lead you in the right direction.

Bob Cox

P.S. My avitar is a picture of the model A biplane. Picture also below. Second pic is the model D. Third pic is the model E.