Interesting considering the couple of times I read Steve Jobs state that he would never get into the tablet PC market as it wasn't really economically viable.
As to an iPad form-factor macbook, its called a ModBook - a third party company that is allowed to modify their notebooks into slates because Apple was unwilling to enter that market.
Again, the same prediction with the iPad applies if they do go ahead with the product. It will be laughed at and bashed up until released, and then the Apple PR machine will go in full gear as people snatch up the "revolutionary" device. Places like Tom's, desperate to post anything Apple to draw clicks (and thus Ad revenue), will snap up all the Apple PR they can to post about it (like the iPad) thus further feeding the frenzy.