___Updated July 10, 2013: Made the clips longer by default.___
This is my first use of a simple concept, to mount parts on the printer using clips that span two rigid points, either from the back of the frame to the front the M8 smooth rod, or between two rods. Parts built this way should be more secure, require no extra hardware, be easy to add/remove, and complement the i3 design.
The first revision only included a Z endstop mount. It worked so well I've added a Y endstop mount that attaches to two bed rods. These are my current results. You may need to tune the SCAD file to get the best fit for your machine. Earlier revisions made the clips a little too short by default.
By default these mounts are set up to hold 20mm x 10.5mm x 6mm endstops. The Z endstop is aligned lengthwise between the rod and the frame. They can be modified to accept any size endstop that will fit in the space, or even outside it with some extra hacking.