Wow, that looks really neat too! ZFS is another one (Merkle tree on block-level checksums, and kind of "distributed" if you squint at zfs send | netcat just right). Not sure if they published about it beyond the code, but some of the ex-Sun blog posts about it are great.

I just read through your Data Package Manager post, and I have to say 1) bravo and 2) I need that - yesterday.

I hope Dropbox doesn't acqui-quash you before these things get out of hand :)