Slot load iMacs only have one PATA controller, however tray loaders (such as the Bondi) actually have two, trouble is that the controller used for the CD-ROM drive has a smaller 50 pin connector, as opposed to the standard 40 pin connector, the only ways I can think to use the secondary controller would be to either make up a cable from an iMac CD-ROM cable and an IDE cable, or to use a 3.5" -> 2.5" HDD adapter in reverse.