My first (and easiest) idea is to generate a friends/villains list for javafibs, but I also want to test out some trust metrics on the vouch/complain graph.
It is exactly what I do manually. It use to put in villains all players which has more than x saved games. In the beginning it was ten games but now I extend that threshold ~ 15-20.
Another source for villains are here:
http://www.fibs.com/savedgames/ where you can find list with players who have saved games. There is also link to bot droppers. I suggest you that you make buttom in JavaFIBS which could read those list and create villains list for all players who has more than X saved games.
RepBot could be also source for players with bad reputation off course.
For friends I put there only players with whom I have to play my FIBS League matches, so I can find it easily on players lists with different color or get a sound when they login.
Anyway thanks for your will to improve playing at FIBS.