How about the manage plugin? I do not see that listed anywhere on this site. However judging by the lovefest I see over this plugin you may wish to show it off as a great use of the plugin architecture.
http://forums.cacti.net/viewtopic.php?t=13827&highlight=manage
It is a big brother/hobbit type plugin that can check the tcp port status of devices as well as monitor service states and other relevant info of devices that you are watching with Cacti.
Pretty cool really.