Purpose-built marine and over-the-road ruggedized mini-split systems:
http://www.cruisencomfortusa.com
A/C only at this time, no heat strips.
Another travelogue blog by full-time RVers with an envelope-pushing solar setup. Happens to be beautifully written, too, particularly the descriptions of all their stops along the route around the country. They recently visited my hemostat of NC and fell in love with Ocracoke Island.