Holy crap $600 for powder coat? I sent mine to get sandblasted and powder coated for $15/wheel. I couldn't even paint them properly for that price.
Yeah, good luck figuring out what to do with the clippings. That's one thing I like about trailers. You have the bed space for the clippings, but then you also have to worry about a trailer. Maybe somebody will come up with the perfect setup. Maybe a cabover landscape truck with a small dump bin right behind the cab.