Tangentially related, Snort was doing research to move to a multi-threaded architecture, but decided against it due to cache synchronization problems [1]. Though, their thoughts about splitting up processing was quite different than what the OP blog post suggests.

It looks like Snort gave up on one way of doing multi-threading, but they could still go the way suggested in the OPs post.

[1] http://securitysauce.blogspot.com/2009/04/snort-30-beta-3-re...