Another things to consider, since you're going to be doing so much checking is to instead of just running a tor client, running an authoritative directory server. If you don't want to deal with all the traffic, you can just set it to only allow local connections and not adversite. Another feature might be to run it through the peerguardian lists (peerguardian.sourceforge.net) and somehow "label" servers in those lists.
Interesting. Opinions? Worth the trouble? Or is using the tor cache enough?