Make your own, it's super easy and almost free.
I did mine out of stainless steel. measure hole, cut a rectangle into your material of choice that is 1/16" longer and wider that your measurement. take a grinder or even a file and give the corners a 1/4 round (round off corners) and bevel the edges from the back side to make a sharp edge. Mount your stuff into the panel. then Squeeze it in from the from, you'll have to sorta fold the the lip around the opening back, but it stays in really well. it's actually a little difficult to take off. holds in like a Chinese finger trap. if you protect your work from scratching, this looks REALLY CLEAN because there's no bolts coming through the face of the panel.