Check out this teahouse that is built atop two chestnut trees. It is located in Nagano Prefecture and is called the takasugi-an teahouse which I believe means a teahouse too-high. The teahouse sways gently when there is a breeze. I don't see how it could stand up to anything more than a breeze though.
The photos and info are from Dezeen.com. There are more photos and information here.