Wow, you're good. I am in a small environment (1 combination Domino mail/application server) with only 50 users. So, I don't have a situation where my server is taxed too heavily. But, I see your point.
My contract network engineer and I decided to go the easiest route, to be honest, and let third part software take care of our situation. It has been fairly effective, although the Interscan had some bugs and needed a patch applied to work optimally. TM NeatSuite w/TM Interscan 3 with content management is loaded on a separate server than my mail, so all incoming/outgoing mail goes to the virus wall/interscan connector to be checked, then comes into my mail server. Nothing really logs that much to my mail server now, except mail routing info, i.e.-sent to ip.address.tmserver, and mail received from same.
But, I will forward your info to my network engineer.
Thanks!