I have made this Minilistic MK7 derived from http://www.thingiverse.com/thing:15718. I felt that I need to have a cleaning brush inserted to automatically clean the extruder pulley.Updated 28-03-2013 8mm hole for brush Updated 29-03-2013 Bottom cut out for stepper motor. Final.Thanks to whosawhatsis for this spring version of Minimalistic MK7. Print using 50% infill, 2 layers. Spring is from Ikea clothes hanger clips Small bearing with inner diameter of an M3 screw.(From my junk box which I think from a old hard disk) Will update the bearing model number later if I can see the imprint.