While I don't know much of the source, I have found a website that claims to have taken pictures of the iPhone nano, though the source is unknown (to me) and I don't know how reliable they are, these pictures look legitimate.
Here's the link.
http://www.unwiredview.com/2007/10/27/first-spy-pics-of-iphone-nano/
Here's the link.
http://www.unwiredview.com/2007/10/27/first-spy-pics-of-iphone-nano/