That is interesting you mention Martrim, though it sounds like you had to defeat the purpose of the exercise by re-stitching them. I'll see if they can send me a sample.
After collecting more than a dozen carpet samples from suppliers in the US and UK (literally a dozen or more), I found the perfect carpet material from Martrim. It is wool and thicker, but the pattern is quite close to the original glove box "bag" carpet in my car.