I don't think Apple would do it anyways. They're about simplicity, and the top part with the trackpad moving adds more little things that could easily break.
This probably the main argument against it id say. As much as i would want an Apple netbook, this isnt very usable for portable use unless it was extremely stable
actually it looks very good to me. When you use the netbook for 'quick' surf you can use the trackpad and if you need more extensive use then you get your keyboard.
However I agree that it is a little bit too complicated... Looking forward to what apple really does. hopefully soon enough