Edit: This is a work in progress, I just uploaded a new version that has notches cut out for the rods. I re-added the holes for the tensioner nut and bolt, a cap to protect the belt from the end of the belt and made a few design improvements. I also changed the LM8UU Bearing Holders to not be snap fit. You'll have to use Zip Ties to keep the Bearings in place.
If you've flipped your Prusa Z Axis to get more build height, like this:
If you're using the standard v2 Prusa X Carriage, you've probably flipped it also so it's back on top of the rods. I noticed that doing this caused the X belt to rub against the mount near the stepper.
I created this so that the X Belt Mounts are longer to account for being flipped.