BitTorrent over I2P exists (and is popular). A torrent client is bundled out of the box. A custom spec exists for this also[1].

As for Tor.. Tor and BitTorrent do not mix; the bandwidth is not available (BitTorrent chokes Tor relays due to model used between them) as well as the amount of data which can be pushed overall. For the most part (though this would not be relevant to a formal BitTorrent over Tor design), BitTorrent is not anonymous as most intend over Tor[2].

[1] http://www.i2p2.de/bittorrent.html

[2] https://blog.torproject.org/blog/bittorrent-over-tor-isnt-go...