According to Alastair Callender, his 190-foot Soliloquy would be able to fully propel itself using a combination of solar power, wind, and hybrid marine power technology. And it looks like a metamorphic alien mothership to boot.
It looks cool, but I have a hard time imagining this titan moving at a decent speed using these technologies. On the other side, if Cousteau's Alcyone ship—with its wind towers—can work, maybe this design could work too.
I would pass even if I had the money to buy it, though. Why would I get a cold, super-expensive super-yacht for a gazillion dollars when I can use the same money for a fast 100%-wind-powered three-mast schooner, with fully automated sail deployment, and have a crew of Scandinavian sailorettes with unbuttoned white shirts, short navy blue skirts, and no panties for the rest of my life? See? Rich people don't know how to spend their money.