I am working on the plans for one now and intend to start building it soon.
For right now I plan on renting it out after its done being constructed. My ultimate goal is it being a place for my wife and I after the kids are grown up. They will probably get the house we live in now as it is far too big. A kind of stay-close-to-the-kids thing, but out in the back 40 where we can live quietly and in a much smaller home. Definitely off-grid, limited access, south facing, etc. I mention all this because there is a heap of difference when a house is built for someone else to stay in, and one designed to keep yourself content. Granted from person to person tastes change, but building something for yourself typically has details that do not go unnoticed by others.
I am not sure on how long it would take to construct; like Paul's Wofati Cabins I have some heavy equipment to make the work go much faster and obviously have the trees.
His brain is the size of a cherry pit! About the size of this ad: