In a perfect world they would all use the same smart media cards (3.3v DUH).
Look at it like Rolands little money making exercise .I looked into the same thing for my SP202 and I have someone I know at roland who said that 4mb is as big as you can get ... on the SP202 and only the roland cards work , But that there was plans for other (read newer) products to go to standard 3.3v Smart media ..just too late for us huh??
I think that the non-Roland 5v cards are slightly different (something about a cut or angled bit going the opposite way)
Bummer Huh?
Mind you if you get one going let me Know !!!