are you monitoring them all in NPM? We've got a similar setup with nexus' and 6500s...looking through the UDT_port table, it looks like UDT is showing the speed that the interface is connected at, not the capability, so not sure how accurate that would be for you. The nexus throws a wrench with all interfaces labeled as Ethernet and at least our speeds are way off.
yes we are monitoring them all through the NPM. I have managed to right a report through the Report Writer to display all tengig connections (by searching for name starts with "te" and "Ethernet1/") that show as Last Seen Never. However some of the interfaces are interlink connections that have physical connections but UDT doesn't pick up any data. I have got around this by searching for interfaces with no description that match that criteria, which is fine as long as we keep the description blank on all unused ports, which doesn't always happen unfortunately.
Its a shame i can't use the Report Writer to report if an interface is inactive as that would work fine. Or have a view that could be edited to be port type specific.