SliderDock is a different dock, it creates a 3D circle where you can add as many applications as you want because the circle can be as big as you want, in fact, Sliderdock will adapt its size to the number of applications in it automatically.
It's very easy to use. You'll see a round interface where an icon is displayed. If you want to add an application to the dock, just drag&drop it. Then when you want to launch an application, place the cursor on the interface and use the mousewheel to find the application you want to launch.
It's easy and fast and you can customize it by changing the theme, size and distance between elements.