It looks like a fun piece, and it doesn't matter whether it's in theme or not.
Have either of you built an installation anywhere else? Do you have any experience with building, either public or private pieces? If not, you should try and get some people on your crew who have that kind of experience. There would be different things to consider depending on what you make it out of (wood, steel, etc) because you want to make sure people don't get splinters, or cut themselves on jagged corners, etc. Regardless of what it's made out of, you need to make sure that it is EXTREMELY rugged. People won't just climb on it, people will CLIMB on it.
I found these two pics from Tristan Savatier
This one was posted by the SF Chronicle
And this picture from Cheryl Gatward
You and your team need to make sure your structure can withstand both the elements and the weight and stress of potentially dozens of participants climbing on it. Anchoring will probably be less of a concern once it's fully assembled, because anything strong enough to support that kind of weight, at 11' high and 32' wide and deep, it's not likely going to blow over (though you'll probably need to anchor it as you're building it in the desert). Good luck with the project!
