Essentially, it was:

http://www.differentpla.net/~roger/empeg/car/cloning.html
http://www.differentpla.net/~roger/empeg/car/rsync.html

But that requires ethernet. However, networking isn't _that_ hard to set up -- you'll need a hub/switch (a cheap 4-port hub will do), and some cables to connect the empegs. You don't have to connect your PC if you don't want to, though I recommend that you do -- synchronisation is up to twice as fast on ethernet vs. USB.