I was looking at their site a while back thinking about building my own three point setup. The only way that works out is with their suspension/tension system they've developed in conjunction with their trampoline type floor. I thought it was a interesting concept but finding three trees spaced appropriately is definitely harder than two in my book.
Here's another weird one for you guys the "Tentsile - Tree Tent"
for any environment they say. The even have one that's supposed to sleep 6-8 people.