Hmm, just been thinking about your problem, and rather than trying to back stuff up to a USB hard drive or something, wouldn't it be possible to just hook it up with one of your computers via a crossover network cable, or even plug it into a switch, and copy all the files you need to onto your computer and burn them onto a cd or DVD? I'm assuming that if you used FeatherLinux or if you got Knoppix working (I don't know anything about Dyne:bolic), you should be able to get networking going, and you wouldn't have to worry about trying to write to an NTFS partition. Hopefully that's of some help.
EDIT - It appears Dyne:bolic has some sort of network support, so maybe give that a try?
