Mine has a wheeze as well, and its louder after a shed. Everyone I have asked has told me it is a stuck scale on the inside of the nose. I'm hoping it eventually comes out, so maybe these other wheezes are just that. Or maybe mine just likes to whistle
I have heard of snakes sneezing, and I think there is even video of it on youtube.
Not the one I was thinking about, but funny none the less.
http://www.youtube.com/watch?v=yG3f6h892SU