I'm not sure what to use for the conductors.
I don't understand what they mean when they say Part A and Part B. Isn't it just one product?
EDIT: Also, If I had a RepRap, could I not just print a 3-d Plastic mold and then just pour it in there?
Those black rings you see on the part from SparkFun are likely the conductors - generally they are carbon-impregnated rubber (not sure where or if you can easily buy that - but I bet some googling would turn up something). You mainly want something that isn't going to corrode or degrade over time. You might be able to make your own by following something like this:http://www.instructables.com/id/Make-Conductive-Glue-and-Glue-a-Circuit/http://www.inklesspress.com/conductive_glue.htm
Oh thats true, although every time you press a button, you'd hear a "clink" noise and it would be a lot heavier, wouldn't it?
Would I just glue them on?GORILLA GLUE!
Yea, I'm just trying to get ideas. I've never done this either.