I was checking out the link for possible new ipod nano photo at alibaba and found some cases for a 2nd generation ipod touch. There looks like there's a little hole on the top left corner in the front of the case - i can only hope that it's for a camera (though it would make it a little hard to take pictures without using the screen as a viewfinder). either that or maybe it's an external speaker.
what else could it be (assuming these are actually real cases for the 2nd gen ipod touch)?
http://www.alibaba.com/product-gs/208809625/silicone_cases_for_iPod_Touch_2nd/showimage.html?
The hole would be for the ambient light sensor. The larger hole on the right could be for a speaker.