I've been wanting to find one of these things for quite some time, with no luck. It's the Japanese-only one that was used with the game Cutie Q on Namco Museum Vol. 2 (the Japanese version, obviously). I just read recently that Bomb Bee is a hidden game on there (my favorite of the Gee Bee/Bomb Bee/Cutie Q trifecta of early Namco Breakout/Pinball-type games (now there's a niche genre for you! (Ach! Triple parentheses!!))), so I've redoubled my efforts (well, my yearning, anyway) to find this controller.
Anyone know of a place where I could snag one? (When/If my fiancee ever comes home, I could have her contact her otaku network of friends in Japan to get on it for me, but that's up in the air indefinitely.)
Here's a pic: