Rosalind - 3:32 pm on Dec 16, 2012 (gmt 0)

Do you have a list of your nutjob's IP addresses? If so you should serve him up a 404 on the whole site, definitely not a 403. There's no reason you should tolerate a troublemaker, and pretending your site is down is fair enough. This approach will work best if you don't let search engines and archive.org cache your pages.