I'm not sure if you've heard of Joe Ades. He used to sell potato peelers in NY and has been mentioned on HN a few times:
http://en.wikipedia.org/wiki/Joe_Ades
http://www.nytimes.com/2009/02/03/nyregion/03ades.html
http://www.youtube.com/watch?v=HCUct4NlxE0
I don't think it really matters what you sell, especially in this case where you just want to improve your sales technique. The main thing is that you sell an experience, not a product.