If you want a tag where the numbers/letters stand in "relief" (like punched from the backside) you might investigate the printing supply industry. There is a technique known as "electrotype" where a zinc casting is made from a black & white positive image. This piece can be made either in reverse (as a printer would use it) or to "read right" which works as a VIN tag. It can be made to include anything that you can put on paper (like with WORD). When the printer uses it , it gets copper plated and mounted on a wood block. When I had one done, it was merely a thin (.050" thick) plate. I attached it with drive screws. Quite inexpensive as I remember -under $30.
my dad has a collection of license plates from like 20's +... so i'm gonna take the 31 plate down to the dmv, with the block number off my 50 olds rocket and the numbers off the body tag and tell them "i need to get a ***le for my dads old 31 chevy thats been sitting for years on our farm and he has lost all the paperwork for it, so i wrote down all the numbers i could find on it, and pulled these plates off it, if this will help." i'll tell you how it works out.
I don't have a picture of it on hand...I'll have to snap one & post it tomorrow. However, my body tag looks very much like the serial number plates pictured here: http://1931chevrolet.com/specs6.htm And yes, I got it from the Datatags.com folks. They can do embosed background and reversed stamped as well. Very quick turnaround.
Tip: Wait for a female clerk and give her the sad puppy eyes look when you hand over yer stuff and pour on the humbleness. Every little edge helps.
The rules are different for every state. A few hours on the state DMV site,studying the Motor Vehicle Code,might help.
http://www.cl***ic-plates.com/index.html I ford this guy when I was looking just email him for a quote.