Something similar exists: iabackup[1][2]. It is designed to host an independent copy of (some of) the Internet Archive using git-annex. You tell it how much storage you want to donate and git-annex fills your disk with data from the least-seeded files IIRC. Its focus is on data backup, not data serving though.

[1]: https://git-annex.branchable.com/design/iabackup/ [2]: https://wiki.archiveteam.org/index.php/INTERNETARCHIVE.BAK/g...