Thanks for the informative article. Very useful to know how to do this.

Do you have any idea or a pointer as to how we might integrate this with existing ad plugins?

like this one for example: Random / Rotating Ads Plugin for WordPress — by datafeedr? you can google it or it is here:

http://www.datafeedr.com/random-ads-plugin.php

oh, btw, the tab order on your comment form seems to be out of order. if I tab after the e-mail field I get to “submit comment” instead of “notify me of follow up comments” just an fyi, but maybe you want it that way. Cheers.