Looks like my research is going to speed up a bit here, since the second 30GB drive finally gave out yesterday.

The one dual CF to single IDE converter I found is this guy, but the reviews, and information in it are poor at best. I'm guessing it's a solution if I wanted 2 cards, with one in the slave, and the other in the master position. That wouldn't get me to 4 cards in the empeg though, since the one adaptor would consume the IDE bus.

Sourcing the parts locally appears to be out now, with the Frys shelf showing an empty slot for the one adaptor they carried (just a normal 1 to 1 converter) with no ETA on a restock.