this is absolutly fantastic!
Eucalyptus Treehouse Los Angeles, California, USA Built in Los Angeles as a young girls' hideaway, this inspired treehouse, a daydreamer's paradise, is nestled within two blue-gum eucalyptus trees. Its curves, structural elements, and detailed finishes - both inside and out - provide a harmonious retreat, along with views stretching 180 degrees from downtown Los Angeles to the Catalina Islands in the Pacific Ocean.
wow. At the link is a full gallery of "Ultimate Tree Houses"