I don't know that I'd dismiss Titus as summarily as Q does, but it's certain that the poem that endures is the one attributed to D'Arcy (now, whether it was written by d'Arcy is another matter, since some say it was attributed to him as the actor who performed it). We still haven't found a complete copy of the Titus text. I guess we need to send an emissary to Ashtabula for that.
But whatever the case, I think we have adequate proof that the poem wasn't written by Robert W. Service.
-Joe Offer-