This is my take on an extruder controller mount for the MK5. It mounts your extruder controller to the right of the plastruder arch support. Originally I had mounted the controller in this position using zip ties through the bottom holes in the board, but this was a quick and dirty way in order to get the bot running. The mount is secured using the existing unused hole in the Z-stage and requires no modifications to the plastruder mount.
STL and SolidWorks 2010 model files included.