I feel your pain. My Carl Zeiss Jena lenses use 86mm filters.
You will find that filters do come up on ebay. I bought mine for about 25EUR each, on various auctions (UV, Linear Polariser, Red, YG and green).
On the original question... no idea. Lee makes glass filters (at least some models) - Cokin made plastic ones. (and I'm not sure if they emerged from the bankrupcy/buyout/whatever happened to them recently).