While I've never competed (I just don't think that art should be judged that way), I'm a pretty fair air guitarist myself. My signature tune is "Hocus Pocus" by Focus.
Actually, I'm kind of concerned about that auction, because I'm willing to bet that the buyer is expecting to receive the empty guitar case, and the description seems to suggest that all he's getting is an empty envelope. I predict negative feedback (speaking of which, I'm a master at air-guitar feedback and sustain, you should hear my Santana medley).