I have a set of grills from one of my X-Statiks, but my only complaint about them is that the metal grills tend to ring, esp at higher volumes. So i took them off and I dont plan to replace them, just remove the mounting posts, fill in the holes & repaint it once the time comes to build/replace the 2nd tower that was sadly damaged in shipping.
You might be able to make a wooden grill if you know someone with a CNC machine, or even out of plastic if you know someone with a 3D printer then covered with some speaker cloth. Should help protect the drivers, while also prevent the ringing issue.