This is a mount + fan housing for connecting two E3D v5 hot-ends to a Rostock MAX 3D Printer.
I modeled this in FreeCAD and then exported the 3 STL files. I'm not an expert modeler, so the FreeCAD creation could certainly be better :-).
Print in ABS and then attach to the Rostock MAX platform using 4 #6-32 3" screws. 2.5" screws should work fine as well.
Note that this mounts UNDER the platform, so you lose about 54mm of build height (mine went from ~361mm to 308mm).
I routed the wires from the hot-ends through the openings between the mount and the platform. Strain-relief would probably be a good addition if anyone wants to add that.