See this potential product. See this thread for some Q&A about it.

From what I gather, it will enable the use of up to 4 physical hard drives on a single IDE channel. It was created for TiVo by the same guy that makes the TurboNet cards. TiVo, like the MkII and MkIIa, only have one IDE channel. This hack would allow more drives from a single controller. Just passing this on as it seems that some of us (Paul Grzelak) could find this useful. If we get FLAC support, it may be essential. The only problem is cramming this interface and 3 to 4 drives into the empeg. But... I think it's still something of interest here.

From that thread:
> How does it look to linux

It looks like one controller (primary) with four drives. They come up as hda, hdb, hdc, and hdd. The only trick is that hdc and hdd normally map to the secondard controller so when you create the dev you have to specify it correctly for the quad configuration, rather than the default 2 controller configuration.