I heard of a quest that came out to introduce TBS. All the undead wandering various zones now drop the quest parts for it.
The result was I heard a 10% undead only slow that had a recast time of about an hour, which translates, to me at least to useless.
My interest was also pricked briefly by the quest for a trap that mezzed undead who walked through it. Unfortunately although the description didnt mention a level cap, it didnt work in Frostcrypt, now that would have been really handy.