Anyone know where I can find a source for the diamond black fabric? I am looking for the source, not just a 1 time purchase.

 

I know that RescueX had his Windjammer modified to be a wrap-around version for the four door at a local upholstery shop. I didn't pay close attention, but I didn't notice that the fabric was not the correct one. So, perhaps contact a local upholstery shop and see where they'd buy it.