Steve Jobs seems to have a big obsession to create a new generation iPod that can wirelessly sync with iTunes. Sure, that way, the USB cable will become obsolete for iPod products. Thus quoted from cultofmac.com.
Instead of importing music, movies, and applications through Apple's 30-pin connector, then the iPod will automatically sync users often connect it to Wi-Fi network.

To tackle the problem, Apple reportedly tested the iPod with carbon fiber material instead of aluminum, which is usually used on the iPod-Apple's previous iPod. Thus, it is expected to more stable signals.
Apple also took Kevin Kenney, a senior engineer with expertise in the field of carbon fiber. Previously, Kenney was a part of Apple and made a number of patents for the company was driven by Steve Jobs.
No further information from Apple, about when the latest iPod will be released. In relation to materials used too, Apple has so far continued to do research.