I wonder if someone will eventually take the innards from a new ipod, and put them into an old ipod (rewiring the buttons and possibly display too, then they could hook up some old ipod batteries on the inside and haven an uber-pod. You could fit the inner workings of a new pod into an old style body, and still have enough room for a couple of old ipod style batteries. But thats from a purely volumetric sense, There are probably some sort of wiring / ligning up issues that would have to be dealt with. And I'm not sure if the old / new batteries are at the same voltage.

... just an idea for an adventurus / rich / wreckless) podder, it would be awesome to see one, imagine if apple released an implementation of this rather than the new ipods - "yeah the design was perfect so we just trippled the battery life and made some firmware changes - have fun!"