They won't do that because they like to keep the DPI relatively constant across their desktop line. Laptops are different because they're meant to be compact and are often used nearer to the eyes. Besides which, if they made the 17" 1680x1050 then they'd have to make the 20" 1920x1200. What could they make the 24"? There aren't any 24" panels over 1920x1200, at least as far as I can tell in the consumer area. If they did somehow get a 2560x1600 24" panel then it would be stepping on the toes of the 30" ACD.