Hi there,
Best option is to find a rusted out/parts truck that has good glass. I have an extra or two but am holding on to them.
There is a guy named "Shane" in TX who has posted here who apparently had molds made. He said he is in talks with the big parts guys (maybe Jeff at IH Parts America?) to sell the molds so that a large order can be done to lower per unit cost. The demand has to be there otherwise it does not pencil out for these guys.
The C Series Travelall is a cool truck but the rear curved quarter glass is hard to find.
Regards,
Dan