I made this... it works perfectly, the caps don't bend at all if the screw is adjusted to the correct depth.
Cost about $5 bucks at HD, all you need is a 3/4" square wooden dowel and some screws. I was able to make about a half dozen out of one dowel so I gave some to friends and also my local beer bar and they're all collecting caps for me (I'm going to cover the bar-top of my future keezer with caps).
Super simple to make, just chop the dowel into ~6-8" sections, drill a pilot hole, and start screw. After the screw is started put a bottle cap upside down on the dowel next to the screw and drive the screw in as far as you can without it touching the cap. Voila, a little sanding and you're ready to go. The screws I used were all longer than the thickness of the wood so I used my Dremel to cut them to a smaller size so they wouldn't cut through the back.