I actually made a magnet link archive a year and something back (
http://www.karelbilek.com/piratebay/ ), mostly as an experiment
Only the magnets and names - 76 MB; all the magnets + descriptions + comments - 631 MB
It's not that workable for any particular usage (other then statistics I guess) and I never upgraded it since then. There were some attempts by other people to regularly archive TPB (and semi-mirror sites like torrentz.eu and bitsnoop were "mirroring it" by reposting its torrents until the very end) but I am not sure if somebody actually dumped it online regularly in an archive