I've got a potential client that wants an ornamental gravel "pond" installed. That is, she wants 3" of gravel laid in the shape of a pond. It will look something like a kidney bean with about a 75 foot perimeter. I'm trying to find a metal retaining edge material, because that's what their architect suggested and that's what they want. So I've been googling around but haven't found anything but plastic edges or gardening services that want to trim my lawn. I'm in the Seattle area, does anyone know of any sources I can use???