Help for old-school SA?

[Mike Jackson]

I work for a large hosting provider. Some of our hosting accounts are 
(effectively) stuck using SA 2.63, since they are using older Redhat 
installs coupled with older versions of the Plesk control panel. (Why 
stuck? Because Plesk and ES2.1 won't recognize post-2 versions, provide 
proper startup options, or write out the proper header-munging rules.) 
Needless to say, SA 2.63 isn't very effective anymore. I will often set up 
SARE rulesets and RulesDuJour, install & configure Razor, lower the Bayes 
autolearn thresholds and minimum message counts, make sure Net::DNS and 
Mail::SPF::Query are installed, and use RBLs within Qmail. It's not all 
that effective, or at least not as effective as they want.

So, what other tools can I add to my arsenal under these circumstances?