Looking through these Floating Dock pictures will give you some good ideas for designing or building your own boat dock.
Here's a Candock docking system floating dock with a ladder on the front and a walkway on the back.
Here's a floating dock on wheels for easy mobility.
Here's a floating dock with a slide and a diving board.
Here's a floating dock with deck rails.
Here's a candock floating dock with swimming area in the center.
Here's a swimming platform floating dock.