This is a customized version of the Ender 5 Mercury One.1 mod. I had two 10mm rods lying around that would fit the X axis and wanted to use the MGN12 rail for a custom CNC project instead. Please check the Printables link for more information as well as a FreeCAD file.

https://www.printables.com/model/1399143-ender-5-mercury-one1-x-10mm-rod-mod

I also think that having the hotend centered between two rails may allow for a larger reachable print area at some point. Later I want to remake the way the heated bed is mounted so that a larger bed can be used while still having the same Ender 5 footprint.

I don’t think this should still be called an Ender 5 and this point. Perhaps a Frankender will do.