Yeah, that is what I was thinking when I specified "remote", although now I realize that probably didn't automatically convey my thoughts. You'd need something low draw enough that it could run off solar, and ideally connect to the cell network for credit cards. I suppose in all but the most remote of places, you'd generally have a road crossing at least every few miles that would presumably have some power lines running alongside, but self contained power would make it all the more attractive.

Although, I'm not certain 36" unicycle tubes would be a commonly stocked item even if the vending machines existed