There are ones with wires across the plate that might work. The other way is to install a shelf with a lip - it can be just a few inches wide, or less, depending on the size of your plate. You paint the shelf the same color as the wall and you barely see it.

You can get hangers that clip to the plate and have a hook to hang it. That way you can unclip the late if you want to use it. I found mine at a hardware store.

But I'd like to be able to use the plate occasionally. Any suggestions for how to hang it so that I can also take it down and use it every now and again? (i.e. the adhesive plate hangers probably won't work.)