A WiFi iPod has one huge value-add: wireless syncing, a feature its never had.
It's embarrasing that the iPhone/iPod Touch/iPad all have WiFi radios (some since 2007, mind you) and they still can't sync music and movies over the air. No sir, it's 2011 and you still have to sync your tunes via an expensive ($19!) and proprietary USB cable. I've been blogging (ahem, ranting) about itsince 2007 and it's patently absurd.
The issue is that aluminum, although strong and green, isn't radio transparent. Because it's a metal (and thus conductive) WiFi performance is terrible in an aluminum sarcophagus. According to Cult, the best solution is a carbon fiber enclosure and Apple's reportedly researching the composite material in upcoming iPods.
According to Cult, the smoking gun is that Apple recently hired a composites engineer, but not just any composites engineer:
The corporate website boasts that Liquidmetal “is a creator of a new metallic, glass, substance that stores energy much better than stainless steel or Titanium” and has “more than twice the strength of Titanium with the processability of plastics.”