There was a rumour when the 2nd or 3rd iphone SDK came out about an HID or BT keyboard interface. Not sure if that went anywhere, but for flights, obscure travel and the like I would certainly take one of my small BT keyboards and just use the iphone.

An odd bit that came out of the last SDK, was that ROUTING for GPS applications was going to be disabled? Meaning, only the resident (ala google) GPS would allow routing and real time directions. That would be quite lame in my opinion.