9 to 5 Mac just posted in interesting claim. The leaked photos of the cases of the upcoming Apple MacBooks show that all ports are on one side. An Apple patent application that raised some attention in January showed a Apple Monitor with a dock behind the screen. An Apple laptop would be docked from the side.
This only would work if all ports are on one side. A dock for a notebook behind a display would be of course a very clean solution. Most notebook docks just waste a lot of desk space.

More details on 9 to 5 Mac. More details about the Apple Display Dock patent can be found in this Gizmodo story from January.