At Wills Watson+Associates one of our specialities is the design of architectural products. We decided to design a better fixing system for secretly attaching interior wall, panels. You might like it:
www.button-fix.com The design is not open source and is patented so it is only available if it is bought from a registered importer or distributor. It does save you a lot of time on site though so you might find it useful in a construction project and its cost is modest.