I haven't myself per say, but my mom-in-laws buy friend is a whole saler in Glendale. He gets alot of cars from the local auction in Phoenix as well as Cali and up North in Nebraska and South Dakota.
He has bought cars,trailers and motor cycles as well as sleds. Not sure about a boat though. but I have went with him on occasion and it looks like a good way to get a rig. But you need to know what you want and how much something is worth before you go so you don't over pay.
Last time we were in Glendale in early April I wentto a auction with him, his buddy had a blueberry or what ever you call those hand held things. And he could look up prices on cars and what the last dozen or so sold for while waiting in line.