This work was inspired by tysonanderson's http://www.thingiverse.com/thing:276089.
I needed a lot shorter mount for adjusting my level sensors to keep the water level just under 50mm tall baskets for a hydroponic system.
Thanks to Tyson posting the openSCAD file, I got a head start and modified it a bit. I created two mounts. The shorter one is 29mm tall, the other measures 40mm. Both have 9.8mm holes for the sensor shaft, the slits for M3 machine screws have a recess that will hold M3 hex nuts so you can adjust them with only a screw driver. The slits distance has not been changed from the original so they would combine with the long rail of the original thing.