Matt:
I've seen some other forums that prevent blitzing, double posting (like the post whoring that happens here by 'accident'), etc.. via a time restriction on posting.
The way it works is it records the time of your last post, and will not allow another post for a minimum of 30 or 60 seconds.
This means a legitimate poster has time to type numerous messages, and is not inconvenienced, but someone who just wants to double post or blitz the board like yesterday will have to take a fair amount more effort.
Just a suggestion...