How to get rid of a really, really annoying member

[cheat-master30]

Just need some advice to get rid of a member who has been banned like 20 times on a ton of accounts, had about 10 IPs banned, went through Miserable Users and Tachy Goes to Coventry and basically won't stay away even though typical user names of theirs have been blocked from names and such like. I've had suggests to shut down registrations, but that would stop legitimate members. I've also heard of moderating new members, but that then leads to legitimate members being inconvenianced when they want to join and have to wait for either their membership or posts to be moderated.

Oh, and is there a way to ban by what is entered in a profile field?