https://cryptocointalk.com/topic/13587-distributed-blockchain/

"Distributed block chain."
(As proposed to David Latapie in irc chat, July 18, 2014)

If you have 100 peers in a swarm, theoretically you only need to have 1% of block chain locally stored or cached.

-Huge reduction in locally stored data, this would allow to change reference wallets/clients  instantly into
 "light" wallets like Electrum, Multibit.
-Fully decentralised in contrast to Electrum, Multibit.
-Dynamically adjusting cache size, using uptime, bandwidth, reachability, size of network, etc.
 (Manual override should of course also be available...)
-Might be easy to implement using Libtorrent (what else ?) as a backbone.
-For long-term "health" of chain seeders are needed, 24-7.

Anyway just a thought I had, inspired by Torrent and Gnu.net, and it is that obvious or a logical thing to do, that there surely must be some projects out there that are already working on it.

EDIT:
Cleaned up typos