Hi All- I plan to buy a 27" 2.8GHz Quad Core i7. Is it possible to add an external monitor to this system. Ideally, I would like the same monitor, resolution etc. but don't see that Apple offers it. If the system supports dual monitors what is the most comparable available even if a smaller size(I really don't want to get into the 30"Cinema) and not an Apple. Is there any extra hardware, cables, adapters, video cards which would also be needed?