TreeHouse Workshop, Located in Seattle, builders specializing in treehouse design and tree house construction for adults and kids.
These things are cool. They will build you one for less than 70k. You provide the trees.
- Build the Ultimate Tree House (spoonful.com)
- 12 Totally Amazing Treehouse Designs (redtri.com)
- World’s biggest tree house (bigpondnews.com)
- A Tree House ‘Coccoon’ For Backyard Camping (And Napping) (earthtechling.com)