Ah yeah, I have the interface unit already. I'm going for an ultimate PC Engine setup - a Super Grafx with a CD-Rom unit and an Arcade card pro. If this winds up working with my Turbo Grafx as well, that's just the cherry on top.
I've seen a few people ask this question before, from googling and looking around the board, but I haven't seen anybody actually answer. I'm guessing these RAU-30 things aren't too popular?