This is the coolest thing I have seen in a long time, and seems so simple, with a on-board generator to keep the outrigger motors running you could fly non stop. http://youtu.be/0U7z4hXTInM
In itself it IS a VERY interesting setup ... However it looks to me he's got a weight issue and was having trouble with his "stability" !?! Looks like he was having trouble maintaining his altitude ... but alas this is and for what it's worth JUST my opinion
It looked pretty stable to me. He showed a couple hands off hover moments in there. I'd like to see a solar charger electric quadcopter.