If I read well the final cost comes up to about 199. Add to that the time, and it can be actually expensier, thought it has the advantage that you would know how to fix it easily. I wonder if it could be linked to multiple controllers so you can make one version that works in GC, DC, PS, and Xbox (ahh, don't forget PC)
The metal pad from Red Octane come about 200, and they have adapters for 25 for other consoles