I was fortunate to find a plastic one made by the C-Thru ruler company (bought out by the company that owns Wescott and discontinued). Its model number is JR-12. A google search yielded several results of some available online. Search for "C-thru T-square ruler JR12".
They have been around for years. Machine design T-Squares, Machine squares. Most all drafting instruments can and are used for Model building, designing. Architectural design instruments, same way. For precision instruments, be prepared for deep pockets. But there are a lot out there that will pass.
Frank
Glazers use them when cutting large lites of glass as in picture windows or store fronts. Never saw a small one suitable for what we do, however. If there's a glass shop near you it'd be a good place to ask about them. Or you could probably make one with a short piece of aluminum angle from the hardware aisle in a home improvement center mounted on a yardstick.
And here, I thought Cody's ruler is Neil!
Anyway, that could be a nice addition to the toolbox. Thanks for the info!
It seems I wasn't alone in admiring the ruler Cody Grivno uses in his instructional videos. It is called a hook ruler. I did some research and found that many "hook" rulers simply have a hole to hang the ruler on a hook. The ruler we want has a small metal bar at one end that forms a 90 degree angle that "hooks" the edge of the material you are working on.
I found my hook ruler here. Although it is made in China, it is high quality and accurate. I have no interest in the company...
http://www.garrettwade.com/steel-layout-hook-rules/p/96T01.14/
Jerry