Longest timed drive ending up in a touchdown...?

Does anyone know where I can find that statistic? I am trying to find it for a very good friend of mine, she looked online but cannot find it anywhere, afraid that is was never recorded. If anyone knows where I might be able to find that information, or if anyone knows, please help me out...I looked on the NFL website and all the obvious ones, she even posted a blog type thing on a website but no one has been able to answer it yet. Thanks!