I've slowly but surely been working on an Arduino-based trivia buzzer system (think Jeopardy). The handheld buzzers are made from 3/4" thin-walled PVC, and the wires for the switch and LEDs are connected to a keystone jack, which is at the bottom of the buzzer.

Credit to jsadusk for the keystone mounting plate (http://www.thingiverse.com/thing:6647), which I added to an endcap I designed in OpenSCAD (file included).

For best results, flip the model 180 degrees about the X or Y axis so the flat part prints down. The keystone jack I'm using is a CAT 3 one from Home Depot, which just barely fits into the shaft of the PVC pipe.

Marked as a work in progress because I still want to round off the edges at the top and bottom, and because my OpenSCAD code is very sloppy. But as you can see, it does work. I included a version that was fixed (keystone_pvc_fixed.stl) for it being non-manifold, though the original file sliced and printed fine on my Printrbot.