It's a pretty standard BIOS.. I've hooked up 160gig hard-drives in external enclosures with no problem.
The IMOD3 went out of production years ago, as the IOpener hacking fad faded away. In fact, pretty much all of the add-on hardware developed for the IOpener is out of production, and BadFlash is the only source with remaining inventory. My favorite is the deep back cases that Mainstreet designed -- gorgeous job, and it fits a standard notebook cdrom. In fact, my top IOpener machine now sports a DVD+/-RW in that case.
... though, I still need to spend some time on the BIOS so that I can actually boot off of it... there's a timeout problem because this drive takes too long to recognize a disc... *sigh*