Carriage for Prusa Mendel with 25mm and two 40mm fan mounts

This is an X-Carriage for a Prusa Mendel or compatible printer with 50mm spacing between horizontal smooth rods.
It has mounts for two 40mm fans for print cooling and a 25mm fan with a ducted shroud for cooling a j head.
It is loosely derived from my previous x-carriage work for dual extrusion.
This is a single extruder j head compatible design which will work with my direct-drive extruder or Greg Frosts geared extruder. As long as the extruder has 50mm M4 bolt spacing with the j head centred, it should be compatible.