Would love to see a monitor for the Novell Groupwise 8 E-Mail system. You have the free Exchange Monitor tool but nothing for other email systems. The groupwise system uses smtp and would like to see something that would monitor the Domains, Post Offices, and internet agents. Just a thought and I am sure there are others that use Groupwise.
Have you looked at Orion APM? It provides several mail monitors, including SMTP that might provide what you're looking for.