I had thought about doing that myself. You could either use AppleScript, or just read through the database files yourself. There is an iTunes Music Library.xml file which could pretty easily be searched for duplicates using some sort of fuzzy logic to find 'near' duplicates, E.G., "The Long Road Home" matches "the lonG road" or even "The long road / some artist / some whatever." Combine that with a weighting on the ID3 tags and you could do a pretty good job.