Where is the "Home Computer" information that prevents syncing with other libraries stored on an iPod Classic? The iPod Classic (and maybe others?) refuses to sync with more than one iTunes library at a time. This is very frustrating when I keep my music on multiple computers.

Where is the "Home Computer" information stored on the iPod? Is it a file? If so where in the iPod filesystem does it live?
I've been able to do this successfully suing rsync to copy my ~/Music/iTunes/ directory from my "Home Computer" to other computers. I don't remember exactly where the magic is, but it is within iTune's metadata.

Once you sync the first time you don't ever need to sync again. The libraries can diverge after that and your iPod will still consider them both to be the same library.