This is just not going to happen. Perhaps a tablet PC device (11"-12" all screen device) , but not a stand alone PDA. EVERY (and I mean every) stand alone PDA manufacturer has migrated to a converged device smartphone. Apple has completely redefined the category, particularly after 2.0 and the App store. Why on earth would I want another device, and EVEN IF I DID, why wouldn't I just buy a 32gb Touch. Once Documents to Go and PocketInformant release their products AND Apple delivers system-wide cut & paste; game, set, match.
If they really want to top that, work on that super slim, SSD only tablet PC that "docks" with an iMac as if it were a slide in DVD (saw that patent app earlier this year). Now you're talking...