I sat down tonight with Adobe Illustrator and a scan of the fabric used in the briefs and banged out the pattern. It actually took a couple of tries. I won't go into details, but the diamonds are not skewed squares, but are instead bilaterally symmetrical diamonds.
If you use illustrator, you'll know what I'm talking about. If you don't, you'll have to trust me when I tell you that I nailed it.
Next step is to find someone that will silk screen it onto fabric. I'm really hoping that the stuff I ordered last night has one that is useable. I'm going for "close enough" when it comes to the briefs fabric, so I'm not going to sweat it too much. I'll need to decide if I'm going to print it myself, or pay someone to do it. At minimum, I think I will pay someone to make the screen, since that involves a lot of supplies that I'd rather not have to buy just to use once.
I will not be posting a picture of the diamond pattern I drew up. Cuz then you could copy it!!!!