The Campus Manager of CiscoWorks LMS 2.5/2.6 has rudimentary forms of such report:

Recently Down Switch Port Report

Unused Down Switch Port Report

Unused Up Switch Port Report

They're not terribly helpful since they don't show how long the ports have been up/down. AFAIK, LMS 3.x addresses that aspect with 90?-day lookback.

The above assumes you have set up Campus Manager User Tracking coverage of the switches you want to report on.