I actualy exchanged some messages with RCPlanebuyer over the weekend. He said he doesn't make them a lot because they are more difficult to make than normal flavorizer bars. I'm sure that's because of the louvers in the plate.
He told me that he's made a few for friends and would make me one for $30 plus shipping. He just doesn't list them on ebay because he figures people wouldn't want to spend that on a plate for a grill that doesn't cost much more to start with.
Mine's still in useable condition, so i didn't order one, but i'm definately gonna consider it should mine become unuseable.