That IS a shame that it didn't get used. It's a beaut.
I always wanted to build a treehouse for my son. Sadly, we're moving to the country just as he stops being a kid. That will be the big disappointment of my life as a parent - that we're moving to the country a little too late for him. Every kid should grow up in the country, I think. City life sucks.
On the other hand, the schools he's had here in Fairfax County are undoubtedly better than he would have had there, I think. It's a wash, perhaps.
So, what holds your treehouse up? I don't see any supports except for the tree itself.