Lookout Loft by Forever Young Tree House, Vermont. The ramp makes the tree house universally accessible.
I love some of the whimsical surprises found at every corner, such as this railing.
The Birdhouse designed by Tree House Workshop in Seattle, WA. The wood used for this tree house was "refurbished" from various other buildings located in WA such as an old factory and many more.
The Canopy Cathedral by Tree House Workshop. We were told this was the most impressive of the tree houses, but I tend to prefer the "smaller scale" designs. The exterior and balcony are lovely, but the "upstairs" where the glass is was just a large waste of space.
Wouldn't you love one of these in your back yards?