This is the official word from Agfa headquarters on RSX II tramsparecny film:

"Production of Agfachrome RSX in sheet film has now been discontinued. 8" x 10" and 4" x 5" (50 sheets) are no longer available, We recently made the last ever production of 4" x 5" (10 sheets)and that stock should continue to be available for some months. Once it has gone, there will be no more.

Kind Regards,

Pierre Muller"