On my Mac Pro at work, I have a 20-inch cinema display, which I like quite a bit. However, the vertical height is not enough for a full page of text. I would like to get a second display which I can put in vertical/portrait orientation and use to view PDF format papers (scientific literature) with room for a single page of text plus the page selector tab on the right in Preview. Here are my questions: 1) Can the Mac Pro use one display in landscape orientation while a second display is in portrait? 2) What size second display will I need? 3) Do any of the Dell displays rotate to give a portrait orientation? 4) Anyone have a specific recommendation? Less expensive is better, and looks are not a priority here.