Summary I used StefanBurger's 2up replacement http://www.thingiverse.com/thing:248059 and liked it a lot. I'm in the process of doing the 3 up upgrade and needed to modify one side of the X-Gantry. Update June 2016, The original that this was based on is gone from Thingiverse and it is required to make use of this part, So I've added a Zip of my entire directory including the RSDOC file which is the source file for my part. Which can be opened with Designscape Mechanical