"IT'S COMING AND IT'S GOING TO BE AMAZING!!!"
Except it's not coming, because it never does, and it won't be amazing, because even if it does finally appear, we'll all know everything there is to know about it LOOONG in advance and there won't be much to get excited about.
Jobs wants to make a game-changer portable computer. This has been his aim for as long as I can remember. The problem is, technology hasn't caught up to his vision, and his mortality is catching up with him. This leaves two possible outcomes:
1) This constant cycle of rumour, speculation and "this time next year" commentary will continue to add up to nothing, as Jobs keeps pulling back on going into production, because the best Apple can do still doesn't measure up to what he wants.
2) Jobs - worried he'll never see the day that cool kids with good hair iChat on their iTabs (or whatever) in Starbucks - goes ahead and launches the damn thing, but it's massively underwhelming to everyone and way too expensive, and while a few people shell out and sit in public places cooing at their overpriced gadget, most people just make do with a crappy netbook or phone, and get on with their lives.
It can't be thin enough or battery-efficient enough until someone invents fast-refresh flexible eInk, preferably with multi-touch capabilities. There have been prototypes of most of those ideas individually, but no one (that I know of) has put them all together, and certainly not affordably. It isn't likely to happen in Jobs' lifetime, and I for one wish he'd just shelve it, with detailed instructions on what he wants the Apple geeks to build when the tech is finally available. Why rush out a half-realised product? It's becoming a bit of a vanity project (like most Apple stock, I suppose).