NOTICE, this part is designed to be added DURING the build. You'll probably have to break a corner (or two) if you want to install these on an existing machine.
The End Stop switches I purchased came mounted on a small board and I couldn't really find a good match here, so I made my own!
You will need (per unit); 2 M3x6mm and one longer (I used 12mm) and 3 nuts. It also helps (a LOT) to have a toothpick and some blu-tack to hold the nut for the clamp (once you get it started, the fit next to the wall should hold the nut flat and allow you to tighten.)
The loop makes a nice bracket to ziptie the cables.
Hope you find this useful!
Update 3 Feb 2017-
I am specifically restricting use for Shiv Integer. You are NOT allowed to use my design in your "Art" pieces. Thank you.
I added a little "slop" so it should print very cleanly with little to no cleanup
(Your mileage may vary.)
I used Bentley's MicroStation CAD software to design the object in 3D then exported to STL.