What about Nortan Disk Doctor?
 

I know a lot of people don't like Nortan but it has saved my butt a number of times. It saved my dying firewire drive 3 momths ago and saved at least something out of every mac I ever owned. (on my 6th one now).

Okay, just in case someone else stumbles across a similar problem, I wanted to bring this issue to an end. I ended up recovering my data in target disk mode using Data Rescue. I then had to reformat and the HD and reinstall Panther (none of the disk utilities could revive it). I got it back up and running and a few days later it crashed hard again. Disk Warrior still tells me that, according to the S.M.A.R.T. report, the drive is working fine. I ended up unplugging the computer and sticking it in the corner. Our new eMac finally arrived, and life is good. I still haven't done anything with the iMac, but the drive is still under warranty (it was an upgrade about a year ago) so I'm going to pull it and get it replaced.

Bottom line... Data Rescue works.

Thanks again one and all.

P.S. I'm now working through troubles with my PowerBook G4. The fun never ends!