I like the idea of this. There are some books that I want on paper, of course, always, because nothing replaces a paper book. But for books where I just want the information or the story handy to me at all times, this is ideal. Some books are about the object of the book itself. Some books are about the information. This is about the information -- and about gadgetry!
My ideal computer is about the size and weight of a school folder. It has a huge screen, and a full-sized keyboard/stylus-input area. (In fact, the keyboard itself is a thing that fits onto the stylus-input area, and is utterly optional; those who don't want it can easily remove it; those who use it and the stylus equally can flap it out of the way; I'm seeing hinges of some sort.) Probably the bulkiest thing on it will be the power supply, the heat-sink, any drives it has to interface with legacy equipment, and the places where it plugs into stuff. Oh, and storage. How could I forget the storage? Um. Maybe not so light as all that, then.
Above all, it is tough and stiff. It is not shock-sensitive; I can drop it on its edge or corner, and the media player might skip. I can sponge it down if someone spills coffee or soda on it; the keyboard itself is all moving parts and nothing electronic; I can toss the keyboard in the dishwasher and pop it back on after it's dry; all the electronics are inside the computer, sealed out of harm's way.
I do want the keyboard to be larger than some people might like, for ease of typing. I can type very fast, and I'm very used to keys that I can feel under my fingers. I touch-type in the dark.