I think the tablet computer idea is a bit of a red herring.
My guess is that they point to the next generation of video-enabled iPod. The problem with video on the 5G iPod is that the screen is way too small, making it inferior (well, arguably, and only in terms of Video) to the PSP and some of the Archos offerings. But, the screen could not be made any bigger due to the real-estate occupied by the click wheel.
So, let the screen cover the whole of the front of the iPod, and replace the click-wheel with some innovative kind of touch-sensitive gesture control on the screen itself. With a little Apple magic, it could be beautiful. Think... nice and shiny, lovely rounded corners, no moving parts, just a screen in your pocket.
But why stop there...? Throw in WiFi and maybe a simple web browser and a VOIP client and <insert wish-list here>, and you've got a tablet-computer-PDA-communications device in your pocket. Except it won't be any of those things... it'll still be an iPod.
Oh well, back to my day job...
Regards
Superleccy
Edit: Sorry petej, just saw your post... didn't mean to steal your idea.