RamLine also made one that is either stainless or plated. I picked one up at a gun show years ago after my kids broke my plastic RamLine mag. Had I realized how good they are, I would have bought every one I could find, but actually the one I have is the only one I've ever seen. It uses a coil spring like their plastic mags so it's easy on the thumb to reload.
I contacted RamLine a couple of years ago to see if they had any plans to offer it again. They didn't seem interested even though I gushed about how good it was.