With campus boards it's useful to have different size rungs. This helps when training different types of grip and so that you can progress to smaller rungs as you improve. However, if you only have a small board then this can be difficult. I was thinking of a concept where the rungs can be made smaller or larger rather than having rungs set to a fixed size. The most complex idea would be to have the rungs sticking through slots in the surface of the board. Winding a handle at the side would move them in or out of the slots. A much more simple method that I have started to use is to start with fairly large rungs and add thin strips of wood above each rungs - held on with clamps at the sides. Has anyone else tried something like this?