Mark,
The RMX MIBs are available through the web GUI via the "Retrieve MIB Files" button in the SNMP setup menu in the web GUI.
I downloaded the MIBs from an RMX on 7.2.1 and did a quick search for what you're looking for, I did not find anything that would give you the functionality you are looking for. Most of the traps and objects in the MIBs seem to be set up to provide alerts about failures and alarms, rather than status updates.
However, it is certainly possible that I missed something. So I would recommend pulling down the MIBs from your RMX and taking a look as well, but it doesn't look like we have that feature at the moment.
