https://secushare.org/ looks promising but hasn't reached prototype status yet
The Internet is broken: https://secushare.org/broken-internet
A visual novel to explain why federated decentralized server systems suck: http://my.pages.de/dsn-vn/
PolderCast: Fast, Robust, and Scalable Architecture for P2P Topic-Based Pub/Sub: https://hal.inria.fr/hal-01555561/document