ya, it doesn't exist yet. Some companies even underclock the 7600/x1600 to avoid heat build up..some also don't and sell you a fry pan of a laptop. If you have your heart set on the 7900/7800 you'll need a 17" lappy
The card won't fit in the 15" chassis because of the additional heat sink and fan required for such a beast video card. I think you are going to have to moce up to the 17" to get what you are looking for.