I just received a Skinit skin for my 160 GB iPod Classic from Skinit.com, it did not fit the back correctly(the 1st 160 GB iPod is thicker than the current one, but they are both considered 6th gen).

After contacting customer support they told me they no longer make ones that fit the 1st 6th Gen iPod 160 GB model. They did give me credit for a new product however.

I guess this is just an FYI to e-mail them 1st if you plan of buying a skin for your iPod to confirm it will fit your model.