You can find a ton of picks with rulers at
http://www.crypto.com/photos/misc/picks/
FYI: For pictures of picks with a ruler in them, first print it out and then, use a photocopier and blow it up/down until it is to scale (that is the ruler in the picture is the same size as a real one). Or alternately, you can use your cmputer to scale the picture up and down before printing so, again, the ruler in the picture matches a real ruler.
Then you can carefully cut the image of the pick out and use it for a template. I know some folks lay the template on their metal stock and spray paint it so the template is forms an unpainted image after you remove the paper. Then you can grind the painted portion away, and TA-DA, a pick.