I was looking around for the tri/quad discs (I'm planning to get this same recorder soon), and couldn't find any. But one seller is including a BD-R TL disc with the recorder, so there must be someone making them out there. I'll wait until Verbatim is producing them anyway.

Pioneer PDP-5020FD, Marantz SR6011
Axiom M5HP, VP160HP, QS8
Sony PS4, surround backs
-Chris