Logic would tell you that since the iBook G4 is a lot thicker than MB, that it should fit. But if I remember correctly, last time I had my G4 open there is a lot of stuff going on down there, and the older style track pad is fairly thin. Plus, I think there is some sort of 'carriage' for the newer style trackpads that is built into the upped frame, so that it can be pushed, and recessed. Not really sure tho, but let me know if you do it cause I would be seriously interested in doing it to mine. Thanks.