I've seen them mounted into thicker frames similar to a shadow box type of thing.. seems to look great like that.
I also mounted some artwork from my brother-in-law in a similar style like that as well. I made a frame 3/4" wide and 1.5" deep. The frame was 9x9" and had a museum board backer that had the acrylic artwork mounted to it with PVA glue.
I frame mine (not very often, though) using brass or copper wire in the corners of the plate to attach it to the backing board. Then I have the framer mount the backing board in a deep frame with a spacer, so that the plate is about 2 cm from the glass. It's real nice!