Just had this idea pop up in my mind. Instead of relying on volunteers mirroring package repositories all around the world, why not utilise BitTorrent protocol to move at the very least some some load unto the users and thus increase download speeds as well as decrease latency?
But as a third party you can not know which clients are using this outdated http mirror. On BitTorrent you can see every participating peers and some of them are probably enduser machines (depending on the actual implementation of OP’s suggestion).