This is a STEP file of my mono-carriage for Xol. It is only compatible with 6mm belts and MGN12H carriages. This is a part designed to be milled from aluminum, please don't try to print it (it won't end well!).
It moves the entire toolhead 3mm closer to the x-rail, improving performance of the system while providing more clearance to doors and idlers. This may require tweaking your probe mount if your probe ends up too close to the nozzle.