WikiTeam has just finished archiving all Wikimedia Commons files up to
2012 (and some more) on the Internet Archive:
https://archive.org/details/wikimediacommons
So far it's about 24 TB of archives and there are also a hundred
torrents you can help seed, ranging from few hundred MB to over a TB,
most around 400 GB.
Everything is documented at
<https://meta.wikimedia.org/wiki/Mirroring_Wikimedia_project_XML_dumps#Media_tarballs>
and if you want here are some ideas to help WikiTeam with coding:
<https://code.google.com/p/wikiteam/issues/list>.
Nemo