The goal is to get a full list of "connected"/"in use" Ethernet ports on the network. However, I cannot seem to find any way to have RME produce on a list of CatOS switch ports, because the only pertinent option available is "Interface" which as I feared reports IOS switch ports only. Am I missing something?
This is not available in RME. The Interfaces custom report option does not include the module port interfaces. The only way to get this data is to use Campus Manager, and run the Port Attributes report. This will give you all ports, but this can be sorted on the operationally up ports.
There is still a bug open, CSCsj78780, to get all of the available attributes added to RME custom reports.