Doesn't vBulletin have an option to disable people from posting links until they've reached a certain post count? I know the JREF forums do this and they use vBulletin. Perhaps stop people from posting links until they have made 10 posts?

Here you go, install this mod and set the option to disallow link posting until someone has made 5 posts:
http://www.vbulletin.org/forum/showthread.php?t=201285

Excellent suggestion Crundy.

It's a good idea Crundy, however I believe it could lead to further issues:

1. Spammers will still spam, only their links won't show up, making their posts still spammy, just confusing.
2. It could lead spammers to posting even more spam in an effort to increase their post count to be able to post links...

I think the better solution is to add some more beef to our Moderator team so that we can ban these spammers. It's not a proactive solution, I know, but banning these spammers will help prevent the same ones from returning in the future...

I'm going to be working on beefing up our moderator team.