Gentlemen; for the simple tag like the one from Wilson Truck Bodies, as shown by Dave, you should easily be able to get them from as source like this:
http://www.metalmarkermfg.com/metal-embossed-tags
In a previous career, I worked for a company that made utility poles, and these types of tags are used on every pole. If I remember correctly, BC Hydro and Manitoba Hydro used some rectangular reverse stamped tags similar to the one posted by Dave. If anyone has a connection at either one of these utilities, you might be able to get them to run off a customized tag or two for free.
Hope that helps!
