I bought a plain First Act guitar strap from Wal-Mart, and it works just fine, but it's boring.
This is a close-up of a new strap I'm making in a kingsmail weave. The photo looks much cooler than the real thing. The rings running along the edges keep it from twisting too much and keep the edge rings in line. I'm experimenting with weaving more small rings into the middle of the strap to keep it from stretching wider, but it's not a big deal, and they're hard to put in anyway. So I've only done it so far on the tapered end (not shown in the photo) to maintain its shape.
In all, it's roughly 6.5 cm (~2.5 in) wide and so far around 27 cm (~10.5 in) long. It'll have to be a few feet long before it becomes useful, but it's going pretty quickly. I still need to figure out how to attach the ends to the guitar in a way that will keep it from scratching the finish. Maybe I'll use leather.
Also, it will be imbued with the power of MËTÄL.
Eventually I guess I'll have a finished photo, and I'll move this to scraps.