That's a great sign, and I have never seen it. I try to find something "new" every time I visit.
Worth a guess? Maybe.
How about the porch of the Riverfront Playhouse, which used to be the Courthouse Theatre? Not that the signs always pertain to their locations, of course.
As for Easter Egg points, let me apologize to everyone up front for feeding the monster - but I like the possibilities. We'll see how that plays out. At least I pulled out of the fourth place tie!