You want me to show you cocoa touch? Jeez, you really think that it wouldn't run on Mac OS/X if there was hardware to support it?
Well that makes it a very limited product. Possible but the market for ebooks/ipod/mid in a tablet format is gonna be small no matter how awesome you make it given that the iPod Touch is a much more portable system that fills the same niche.
The compelling route would be as an eventual MB replacement and Apple needs to do this to justify a $999 price point for comfortable ASPs and margins. The MB just isn't going to be any more viable than desktops in the future.
Which is easily solved with a MBA like convertible tablet. Or a tablet that docks into a notebook base.
Nope. Nobody cares how much sweat a programmer has to go through to produce a good app if this apps exist. You can have the most brilliant APIs and if no one is coding to them it doesn't matter. And it doesn't matter anyways because Apple already has Cocoa Touch which is based on the core Cocoa API.
You mean fringe elements like students? You need to explain why a student is going to pony up $999 for a MB and another $500+ for an iTablet vs just buying an iTablet that can replace the MB for $999 AND be a multi-touch tablet with a stylus.
Multitouch is not a panacea for all UI issues. If finger interaction was the end all and be all of input methods we'd all still be finger painting rather than using more precise writing mechanisms like pencils and pens.
So you think that folks are going to buy a video iPod too big to fit in their pockets or an ebook reader?
Sure. It's a great MID/PDA combo. And phone too for the iPhone.
Given that the iPhone OSX is the Mac OSX refactored to fit a phone I'd call BS. That's like saying "because you have a mouse and keyboard on Mac OS you can never have FrontRow and a remote" for a better media viewing environment for the user.
Mac OSX is more than capable of being a good tablet OS and be able to morph when multitouch is optimal, then to when a stylus is optimal, to when a remote control is most useful and to when a keyboard and mouse is optimal.