Here is a list of some 3rd party disk suppliers I've collected from info-iris emails.
Comments are from the original poster.
These drives get way to hot and the Indy's can not push enought air through them to properly cool the drive. If one of these drives is put inside an Indy, the drive WILL burn itself out. These same drives HAVE been know to work fine inside Indigo2's . It's true that more recent barracuda drives tend to run cooler than the original ones, but I'm not sure if they are enough cooler. Two of the quantum 4GB or IBM Ultrastar drives isn't a problem, and 3 shouldn't be either, as long as you keep all the plastics on, so the airflow goes where it is supposed to.