Thanks! I just download BeSweet (seemed like the best idea for what I was doing), and after downloading the GUI and the VOB input .dll, I was set to go! I tested it on a key scene that I will be redoing, and it split the .vob in 6 mono .wav's splendidly. I had never realized before how different all of the surround channels were (the voices were all relegated to one speaker, and didn't leak into any of the other channels.

Dubbing Anakin's voice is going to be a lot easier than I expected, especially with DVD Shrink and Sound Forge.

Thanks again for the help!

EDIT: One more quick question. The finished audio mix for my film will not be 5.1 surround; I simply have too many non-surround sources I'm splicing in, and I'm not able to create 5.1 right now. I'd like your advice, though:
Should I use a stereo downmix of the DVD 5.1 track for the base, or if I should use the VHS stereo track, which might be Pro-Logic compatible?