I purchased the Domino starter kit and have the following suggestions:
Add a prototype/DIY component. This is a component with a JSF33AA jack, signal and power rails and an area of holes for soldering transistors etc. Allows the customer to build their own components. Could do single, double or triple versions. Could also have an area where pins could be added to make it compatible with a prototyping board.
Add a holder into which you can snap components. This stops domino/component shield from looking like Medusa.