My prediction is that SP4 will have the same physical screen size but perhaps not quite as much wasted space around the edges. I would like to see the Windows button on the screen go away and place a windows key on the side of the screen like the power on button. I also predict that a new & slightly improved keyboard will be designed that is stiffer (probably causing it to be slightly heavier) and with some key placement improvement like the OP was talking about.