I've seen the future...
Putting the hints all together: it's a letter-sized tablet with full OS X with handwriting recognition etc., BUT, put it on its stand (previously known as a 'dock'), and you can use the wireless keyboard and mouse and hey presto: instant flat-screen iMac. So it's basically a desktop Mac, but you get to carry the screen/Mac off with you. That's why it will go where no PC has gone before, and why we'll all be blown away. Essentially, an OS X tablet/iMac with bits and pieces borrowed from the Newton. The clever part will be the balance between how much Apple squeeze into the tablet, and how much they leave in the dock. And here's why this would be so cool: My PDA's fun, but it's essentially a toy. But a full-sized tablet that can be slipped in my briefcase, and which gives me FULL functionality and even Office v.X and UNIX and everything else on my desktop machine would be FANTASTIC. Ok, I love reading all the speculation, but I think this is the one to hope for.