Open, it looks like, to anyone brave enough to submit something. A few interesting books in the resources list--including Lloyd Kahn's Shelter and the book about Simon Velez, both of which I know about, and the results of a treehouse competition, which I don't.
Hey, you've got until January to submit something.
http://www.bamboocompetition.com/index.html
Some beautiful construction! I've always liked bamboo - we were going to try & grow some down by our spring & pond - someday ::) - now that Glenn has his big toy (bobcat) he can get down there easier. I have a friend who put in bamboo flooring recently, also, put bamboo fencing along the backyard fence already there because she liked the look better. Our neighbors in the valley are growing the large bamboo. As a kid we used to play around the "bamboo" - there would be large clumps growing by ponds - none of those areas left now - all housing developments. The bamboo that grew there wasn't very big, don't know what type it was...
Don't think we'll get in on the contest this year...