Storage? I am Storage!
Doug, you probably know about this already, but just in case .... On one of the wikis I run, spam was a problem until I installed recaptcha - http://recaptcha.net/ - whick killed it stone dead. Free, good cause, very easy to use, recomended. If you want something to lock the bots out, this has worked for me. It even has a ready-made plug-in for Mediawiki, so I imagine getting it to work with vBulletin would be falling of a log easy.