Ping for an interesting ductless mini-split heat pump system with wall mount or ceiling cassettes that I’ve encountered, designed for solar:
http://kingtecsolar.com/products/solarcoolingsystems-k25ft-4/
They have both west coast (CA) and east coast (SC) offices, sound pretty established. There are a lot of home-brewed systems that guys are cobbling together using Chinese components, relabeling and selling, but this one seems not so fly-by-night.
Here’s a link to Technomadia, a blog dealing with live-aboard RVing, including various innovative technical solutions they’ve put together, including a fairly comprehensive entry regarding solar-powered A/C in an RV.