Even though the events that take place in "A Rose for Emily" may not be based on any known historical incident, the themes Faulkner explores in the story accurately reflect important elements of life in the South in the late 1800s and early 1900s.
The conflict of the Old South, represented by Miss Emily, and the New South, represented by the town, is still, in the 21stC, an issue in parts of the South. Miss Emily is a vestige of the aristocratic South that all but disappeared in the decades after the Civil War, but the town, still itself holding onto the Old South, treats her with a gentleness that they would not accord to a younger middle-class resident of Jefferson. When representatives of the town council visit Miss Emily in order to try to get her to pay taxes, they cannot overcome her argument that she owes no taxes because, at some point in the past, the leader of the community remitted her taxes for a loan her father made to the town.
In a second instance, when a smell coming from Miss Emily's house becomes a town problem, the town council simply can't discuss the problem with Miss Emily because they can't "accuse a lady to her face of smelling bad." In fact, they find such a discussion so distasteful that they visit her house at night and spread lime in order to combat the offensive odor. Again, Miss Emily's former position in this society protects her from the kind of unpleasantness a "New South" resident of Jefferson would have to face.
During an interview in 1959, Faulkner was asked why he titled the story as he did. Among other things, he said that he felt Miss Emily deserved a rose, a symbol of love and beauty, because she led such a horrible life. Her father, an incredibly selfish person, had rejected all of Miss Emily's suitors because they were not, according to him, good enough for her. This repression doomed her to a life of servitude to her father and denied her the natural life of an aristocratic southern woman--love of a husband, having children, having a normal home and life. Faulkner acknowledged that what she did with respect to her suitor, Homer, was a serious ethical and moral breach, but Faulkner also said that if a normal life is thwarted by repression, the desire for a normal life is going to come out somehow and often in a horrible way.
Ultimately, we can't point to a real-life example that parallels Miss Emily's story, but we can see that, given the circumstances of her life, such a thing could have happened in exactly that way.