Welding steel can be purchased from OSH depending on size from 12 - 25 dollars (U.S.) Combine that with a framing kit and your set for a much beetter looking tray. You can also add a woodland senic grass sheet and cover the steel for a nice look.
Here is a tray done with welding steel and a desert sheet from woodland senics.
The models hang great and have no trouble fliping this tray on its side.