I'm building my back grill for the rear exhaust on the case. But it will be a mirror of this one, from a construction standpoint.
Cut the acrylic to size, tap the holes in the corners:
Add on a vinyl covering that makes it look like carbon fiber:
And then bolt it into the PSU cover with stanoffs under it to give enough space between the mag and the center of the fan:
more later after I finish the rear exhaust!