I’ve wanted to build one of these for a few years now. Last week I pulled out all my partial PLA filament rolls and began the long printing process. For the most part, everything printed without issue, although I did run out of silver PLA near the end of one part.
With the printing process done, I had to settle on a build size. In the end, I decided that this MPCNC is just going to be a trial run to learn how it works. To that end, I decided on an 18" x 12" work area. I’ve also wanted to use as many parts that I had on hand as I could. I have a sizable inventory of used/old 3d printer parts and an old Rigidbot that I de-commissioned a couple years ago. Steppers came from the Rigidbot and a Prusa MMU kit that I recently decommissioned. I had/have almost 100 bearings on hand from when my son was making/selling fidget spinners. Most were sealed (didn’t spin well on fidget spinners so they never got used. 
).
In the end, I had to purchase conduit, wire, bolts and screws. I did have to cobble together a lead screw/nut system from the Rigidbot that’s not ideal, but it works (lose about 1/2" on the Z axis). Also, I’m using older ramps boards 1) Ramps 1.3 with Taurino Power Arduino and/or Sainsmart 2 in 1 (which is also Ramps 1.3). This took a little trial and error in Marlin since the boards are old enough that I didn’t have any documentation and couldn’t find any versions on the boards themselves.
I decided to run the wiring and install the end stops for the dual end stop configuration, but actually connected it as a normal series MPCNC. If I decide to experiment with dual end stops in the future, the wiring is already in place.
I’ve attached the first Crown print. Please note that I had a pen zip tied into the tool mount and the MPCNC has not been leveled or squared, it’s just sitting on my dining room table. 
It will get leveled and squared when I mount it properly to an old table in my garage. Also, I have already adjusted the the 16 tooth gear in the second video so it doesn’t rub. 
I plan to experiment with this MPCNC and slowly accumulate parts for a proper build in the future, once I know what size I really need and what materials I want to work with.
Gantry goes together - https://www.youtube.com/watch?v=9rWKcenxPNY
First attempt and printing the Crown - https://www.youtube.com/watch?v=rUg1mQ9K6tM
