The original y-motor mount for Prusa i3 looked flimsy, as the motor is only fastened on two of the screw holes. I decided to make one in 10mm thick aluminium. I did this by making a design in SketchUp, exporting the measurements and printing out a template with accurate dimensions.
I milled out a 20mm channel to allow for a belt drive, although it wound up not being neccesary. Looks nice though.
The corners were rounded on a disk sander.
I really like this piece, turned out better than I expected.