I had a dock for my Thinkpad X200. It was a chunk of plastic the same size as the laptop but it also had a bay for a disc drive (since the laptop didn't have one) and also had a pop-out connector for charging a second battery. Since it was the same footprint, it didn't take up any extra desk space and still allowed you to use the laptop's own ports too (except for power), it just made the laptop thicker. And you could even take the dock on the go if you really needed the extra I/O and disc drive. Pretty innovative design when docks at the time were just a big box at the rear of the assembly.