A friend of mine is in the same situation, he has a pair of classic Recaros he plans on putting in a 1966 Mustang. He's looking at this guy on eBay:
https://www.ebay.com/usr/zoomzoomzoo...p2047675.l2559 This seller specializes in German cars, but told my friend he could also do seat covers to match his Mustang.
I don't have personal experience with him but I did some checking with my BMW contacts, and got good feedback on the quality of his work.