I've never seen the movie Rosemary's Baby and won't, not ever, chicken that I am. From what I know of it, I think the story from the movie lends itself pretty well to Mary and Sam though. I like the graphic design done for the original poster by Stephen Frankfurt.
Here's the original.
I've wanted a SPN version for a while so here's what I managed.
Mary's face is from a cap from homeofthenutty from the Pilot. The foreground is loosely based on a cap from Swan Song.