I have planted 6 living tree houses; I have found others who are doing
the same. These are rings of trees planted close toghter so that they
graft and grow together; the thought is to grow solid walls with a
stone or slab floor.
Perhaps you visualized you house high in a tree, in that case I would
find several large trees and pollard them until you have the desired
house form I think it could be well established in 5 to 7 years.
Richard Reames
Arborsmith Studios
http://www.arborsmith.com