It's supposed to be around ten inches, which I assume is a diagonal measurement of the display. Looking around for something that size I found How to Build a Tin Canoe. First piece of good news, that book fits in my trusty Coach backpack. That looks good for Apple.
iSlate is rumored to be the name based on Apple picking up that URL, so that's what I'm gonna call it. A while ago I came up with an ideal application for something like that. I envision an application of this device called the iSlate Executive Reader.
In my scenario the Executive Reader would work in concert with a regular computer with a keyboard. The content the executive wanted to read could be pushed to the reader via bluetooth or other wireless protocol. So they could sit on the sofa in their office and read through reports or email. If this executive wanted to compose a full reply then they'd get up and sit down at their desk again and use the keyboard.
I basically see it like an extra monitor as well. So you could just drag and drop stuff off your desktop over to the iSlate. Then pick it up and walk off down the hall to visit some cubicle dweller where you can wave it in their face and point to it and say, "What about this? Huh? Explain this right here." I can imagine all kinds of business applications for this device that ultimately reduce printing and paper waste and improve team work.
Of course my fantasy also includes a workplace that buys equipment from Apple, which has never happened to me yet, but I've heard it exists. They have more Apple stuff in academics, so how about a use there?
It would be really handy when you're working on writing a research paper and you want to refer to a PDF of a journal article that you could pull up on the iSlate and not have to click back and forth through so many windows on your screen. You could practice the ergonomically recommended practice of not staying in the same position too long if you could pick up this thing and lean back in your chair or stand up and move about to study the article. Still productive, but with less repetitive stress.