There is no way to to elimanate someone on a phone connection. I use a dial up and my IP address is different every time I connect, but when I connect through the connection at work (not sure what they got - but its a heck of lot faster then my dial up) I am on the same dial up.

Banning email is the same, but more effective. At least you make them go through the work of creating new email accounts. In a few years when dial up goes away it will be easy as everyone has a permanent IP - but then you will always have the problem with people that use one IP masking tool or another.

So the short answer is no - you can not ban a user permanently no matter how hard you try.

I dont know what the igonore hack is, but his is what would work the best. If a hack would let that problem user see his messages, but they would only show up for him - not the rest of the users - than he would effectively get board as he thinks nobody is reacting to his statements and move on.