You could just make one out of some light tooling leather, that way you could dye it to what ever color you wanted, and even wet form it to get a full custom fit to your razor. If you are really daring you could do some tooling on it as well. I bought a piece of 2oz tooling leather for making fire steel loops on my sheaths that is about 24'X18" and it cost $10. I have a couple of razors without cases, maybe today I will make a sheath for one of them to see how much work it is and how long it would take.
It does help that I have most of the leather working tools I need for the job so for someone starting from scratch it wouldn't be a savings.