Need a focusing scale

[Farside]

I'm posting in the hope that someone might have an old beat-up for-parts folding bed camera. I need two focusing scales; the most important one is a 150mm (or even two of them), but I could do with a 180mm too.

To illustrate the kind of thing I mean, have a look at this:
Click here to see on Ebay
I could make one out of cardboard and mark it with a pen, but that looks really hooky.