Those laser engraving pics someone posted, looked really nice and unobtrusive!
Check out this site and all the crazy ways they can mark things! http://www.gtschmidt.com/videos/index.html
We do custom engraving with Epilog lasers. If you are interested please let me know. I can send you some pictures of our engraved tools or you can see some at our website www.mychannellocktools.com