Hi Jager - I like the motor mounts on the X and Y axis'. I can't tell from the picture how it is done.
It looks like you turned the boss on the original motor mount to be an alignment pilot for the tubing the goes out to the flange that mounts the motor. If this is correct, did it automatically align the motor shaft and the screw shaft to the accuracy of the machine work? Is there a slot or hole to adjust the coupling?