I think your right, something that large and symetrical with Cardboard, he as to have some sort of assist to get the carboard to bend like it does... maybe he soaks it and presses it into a mold, and that would be cheating also...
P.S. I sent you an email Adam, and you inbox is perpetually full with what I assume is the endless amounts of noobish questions you must get, either that, or you just keep it full to keep questions out, which I am begining to see why you would do such a thing... lol