I have played this on a different server. It is called Super T. there is one T and he/she has 10,000(u can adjust it to a reasonable amount, maybe 100,000) health. Then the rest of the people are detectives and you have to kill the t.
Juggernaut rounds have been suggested before. I enjoy the semi-realistic TTT we currently have where everyone has equal health. The reason our current Fun Rounds are excellent ideas is because it puts everyone on the same level; same health; same weapon.