ObjectDock Docklets are built on an SDK freely distributed.
Here: Docklet SDK
I will investigate a source code for RocketDock, as I believe that RocketDock also uses the same SDK for Docklet builds.
There is also the following resource. This has been apparently abandoned, or just ignored, but maybe of assistance:xDockManager
Unknown from what this was originally developed.
I will see if I can contact Skunkie, but I have not heard from the RocketDock dev team in some time.
Let me know what else you require, and also be aware that I am no programmer by any means, so if you require something, you may have to be Lamen in your description.