Search doubles by title or something else?
Perhaps the sorting capabilities will fit your needs. Or you try the extensions which I wrote:
http://www.sendspace.com/file/em6xklIt filters for entries by title which are more than once in the database.
Copy the file ge_finddoubles.py into the extension subdirectory of your griffith installation.
Enable the extension in the preferences -> extensions dialog (labelled "Find Doubles")
You will get a new button in the toolbar.