I add this because I can not find the dual head mount stl file.
I started at the Replikeo site and drilled down into the Reprap links to no avail.
The pictures show it but no link to the file.
Replikeo Prusa I3 Rework, Ramps 1.4, Marlin, Pronterface, Tinkercad.
Plan B is always to be somebody else.