I haven't heard anything officially but it would make perfect sense from a production standpoint since they could base a lot off the same form factor.
It would be great to see it include "iPhone generation" features sans the phone and web feature. I'd definitely love to take notes with the virtual keyboard, have my address book handy, etc. Cyan Worlds made a port of Myst for the Pocket PC.
I would be even better to place Myst on an "iPhone Generation" iPod with game because of the touch feature. Kind of like the Wii of handhelds. The whole linking book effect would be really fun. Of course this is coming from a long time Myst fan.
I think they might wait a few months till after the initial iPhone hype wears down. Maybe at the Paris Expo they will say something.
I saw that mock up a long time ago before the iPhone was introduced. Last year sometime. However I do with the iPhone had the option for a virtual scroll well. I sometimes find that more intuative as much as I like the finger scrolling or coverflow I find I have a bit more control with the scroll wheel but maybe i'm just used to it.
Isn't it nice to know that we (iPhone owners) have the best iPod? Now I don't have to look at my Nano when Apple introduces a new iPod thinking, "Why don't I have that one? It's so much better than mine."