Check the local gun shops for a contact with somebody who stamps military-style dogtags. The ones stamped on the old addressograph-type machines are raised lettering. Depending on the size and configuration of the tag you need, you may be able to fit an aluminum blank of the desired size in the carrier on the dogtag stamper. If you can't find aluminum sheet scrap of the right gauge anywhere else, hit the junk store for an aluminum cookie baking sheet. Glad it turned out to be the data plate, and not the VIN!