I've been trying to improve print quality lately and I've attempted to add the compact Bowden extruder to my Wilson II. There are plenty of motor mount designs, but I wanted to avoid too much incompatibility and calibration weirdness so I carved up the original Wilson II hot end mount and posted the results at http://www.thingiverse.com/thing:1471742
The main changes were removing anything related to the filament tensioner and the stepper motor mount, then adding material near the filament inlet and by the fan duct mounting lug. The main problem I'm having now is that the hot end fit is too snug and it's difficult aligning the hot end with the filament guide tube. At present, I'm attacking the part with a file to make more space for the bushing on top of the hot end.
The design is far from optimal; it should probably have more fillets and rounding so it doesn't catch on stray wires or have too much stress at inside corners. Importantly, the bottom of the part is not flat, causing Cura to print a few spurious 'islands' before laying down what should really be the main first layer. The workaround is to tell Cura to sink the part into the print bed by about 0.5 mm; this dimension isn't critical and it ensures a solid bond to the print bed. The right answer is to fix that in Sketchup, but I can't even detect the problem in Sketchup, let alone solve it, so I posted the bed sink workaround.
Comments and suggestions on the part are welcome; my background is in engineering but I'm an analyst, not a designer so set your expectations accordingly...
Maybe the right answer going forward is to adjust the existing hot end mount design to allow a push-fit connector to be mounted on top so either direct-drive or Bowden extrusion is possible without replacing the mount. It would simplify matters and make a nice add a Bowden extruder to this kit for only $10-20 upsell option.