Detailed build instructions here:
UPDATE #3 - I have re-uploaded the files after tweaking the hole sizes and the strain relief. I have printed over 20 of these now and feel its time to take off the "work in progress" status
UPDATE #2 - Mistake in commenting meant the previous update did not have the hole in the prusa lower mount clamp - scad and stls fixed now.
UPDATE - If you downloaded the panelolu.scad or panelolu front_left.stl, I have updated the files due to an error that had the letters reversed and a couple of other problems that are now fixed.
The firmware changes required to Marlin to make it work are documented on this blog post:
OpenSCAD file now available.
The knob is tommyc's adaptation of this: thingiverse.com/thing:17404