I see that Apple computers are now supporting DisplayPort. As far as I know, DisplayPort can handle multiple monitors (a sort of USB stuff for video). My question is: how many monitors can I connect to an iMac? Start on the principle that a 20" model can output 1920x1080 pixels and the 27" can output 2560x1440 pixels what resolution will I have on the other monitors? The same? less? How it works? thanks for the help.