How difficult is it to create new configurations

This depends on how sophisticated you want to get in driving the back-lighting and functionality. It also can depend on how well an aircraft is modeled:

• Does the plane react to the standard X-Plane commands and datarefs?
• Have datarefs and commands been defined for any of the plane’s unique features?
• How well documented are those datarefs and commands?

You will need to have a working knowledge of datarefs and commands but the X-KeyPad tutorial videos will bring you up to speed. There are also a fair number of sample configurations that you can use as a starting point.