I've got a modded PS3, I should at least be able to gain access to unencrypted copies of the raw data files that way. Whether or not the sound will be in a useful format is another question. (I would have to set up said PS3 though, as it's currently packed away.)
If all else fails, there's always the analog loophole (ie: turn the music right down, record gameplay, and manually clip the sounds you want out of the gameplay footage using a sound editor).