Well I dont know if this will help any but OperServ has a nifty little command (if supported by your network).
KILLCLONES
Syntax:
/msg OperServ KILLCLONES nick Kills all users who have the same hostname as nick. A
temporary AKILL, in the form *@host, is added to
prevent the offending clients from immediately
reconnecting. A wallops is also sent indicating who
used the command, which host was affected and how many
users were killed. It's usefull for removing numerous
clones from the network.
Limited to Services operators. NOTE: The above command was found at this web page 
