Well, I'm pretty sure that this is hosed beyond all help, but I'll throw it out there on the off chance that I've missed something.
On one of my machines I'm running a file system with 16KB clusters, which limits the size of data on a single partition to 256GB (unfortunately for me, I didn't research that earlier). Anyway, I managed to exceed this limit by a good amount before the file system exploded and I was unable to access any files in the directory that I had been adding new data to (all other directories/files were unaffected). Is there any way you gurus know of to save the affected files? The machine is running Debian (release Woody I believe, don't ask).