My friend Capellan Citizen (creator of ttt_indianisland and it's variants) has started to construct a new map and it has a traitor tester. If you see him around you can talk to him about it but I would suggest trying this,
http://ldt-clan.com/forum/threads/2462-TUTORIAL-TTT-Traitor-Tester. It's the first thing that comes up when you google TTT traitor tester.