I think you've done a great job graphically, though I do agree with Franks comment.
Along the lines of what Doug was referring to I understand what he is getting at but I don't know that any more is absolutely necessary.
It is hard to say what my first impression of the picture would be with out reading the title first. Perhaps one more piece to the puzzle would undoubtedly show that he is a lightning rod sales man, like not only showing the lighting rod that is mounted to the building but also showing a row of some that are for sale or a price on the sign for instance.
But on the other hand he certainly does look like a salesman, and what other reason would you post a sign that said 'lighting rods' other than if you were to sell them? It is a mystery of sorts and I can make up my own story.
Either way it is an absurd comedy, I quite enjoy absurd comedy.