Here's a radically simple way to discourage people from stealing your iPod: prevent them from being able to charge it. Yep, that's the new concept that Apple has filed as patent.

You know how the iTunes in your computer instantly recognizes if that iPod is the one it's matched with? Well that's the little trick that Apple wants to employ in the new anti-theft concept. If the iTunes in your computer fails to recognize the iPod as the one matched to it, it sends out a command to the iPod so that it will not allow further charging.

The concept would work for any device with a rechargeable battery because the device recognizes the charger. All it needs is a little modification to commit "recharge harakiri" on command. Here's how Apple describes it in their filing:
 

For devices that are mainly powered by a rechargeable-power-supply (eg. music-players, phones, Personal Digital Assistants), disabling the recharger effectively renders the device inoperable when the power of the main power-supply has run out. As such, disabling the recharger should serve as a deterrent to theft.

How about an iPod taser? That'll be a real effective deterrent to theft.