Not a tree house, but a very cool and old house in the trees. An old settlement in the Scottish Highlands. <---- This place looks magical! Like the home of the three witches in The Black Cauldron or a house in the Shire!
Gatehouse to Ardverickie Estate next to Loch Laggen ~ Scotland, Series "Monarch of the Glen" was filmed here. * would LOVE to incorporate a tower. Small, albeit, but a couple levels perhaps with telescope tower on top.