This doesn't completely answer your question, but I wrote a script to Monitor Exchange Servers. (It was written for E2k3, but should work on E2k7, but E2k10 is iffy). As it stands now, it checks that the servers specified are pingable, Exchange Services are running, Connectors are running, Datastores are mounted, and the Transaction log drives are at least 50% full (the threshold of which can of course be changed.)
I have this running as a scheduled task every 10 minutes, sending an email/pager alert if a problem is detected. This works best if you have a standalone SMTP server (say a small Linux/Unix sendmail server sitting quietly somewhere), as nothing will happen if your mail environment is broken at a single-point-of-failure...
Another way to get around this limitation (of SPoF) is to make a modified copy intended to run from a command prompt and just print the results to the screen.
This is not to say that you couldn't modify it to output a file format of your choosing (html/json/xml) for a Dashboard to read-in, or trigger other kinds of alerts. You're only limited by your imagination.