After my original make proved popular and numerous requests for the files, I offer this re-mix.
Reduced the height by 10mm, but increased the length by 10mm so I can mount the fan on the end plate instead.
Moved the fan vents onto the end-plate and increased the size for a 40mm fan.
Added the Gyrobot logo so it will not look out of place on my Dual Orca 0.43. There is something very Asimov about a machine printing it's own upgrades.
My printer doesn't have the LCD screen so if you need exit channels for this then you are welcome to modify the OpenSCAD source file and upload the remix.
Modified OpenSCAD file attached, if anyone wants a further play.