Solar Survival has started compiling a list of which US counties will let you build a house or structure with minimal interference and cost from zoning. This seems like pretty useful information for those of us thinking about building various odd sorts of homes or adding... enhancements....
http://earthship.com/Earthship-Designs/pockets-of-freedom.html
http://earthship.com/Earthship-Designs/pockets-of-freedom.html