I think that the solution might be to simply delete characters (not block IPs, since we all know how much of a solution that can be). To prevent the making of new characters as shouting bots, restrict shouting to say, level 5 and above.
This way, a player would actually have to do a little work before it could become a shouter and deleting one of the shouting bots would actually have some effect, for a while at least.
Until the leveling bot got the shouting bot to level 5 and then it could shout.
