I can't really call this a horror story, because we ended up buying the house in question, but we had the same issue that the OP mentioned.
We were looking at a wonderfully maintained three bedroom home and loving everything about it. Then, I asked my realtor where the third bedroom was. And I was embarrassed when she explained that the "formal dining room" was the third bedroom. My realtor said it was illegal for the house to be listed as three bedrooms (for this exact reason, it tricked us into getting into the house and falling in love), and she could report the selling realtor. But since we wanted it, we didn't. It was shady, but it worked. Only one couple ever lived in the home, and never had children, so they turned the third bedroom into the dining room. Which, in itself, would have been fine and easy to close up the doorway to the kitchen to make it a bedroom again. Except, they attached a sunroom to the back of the house, and now that dining room window opens into it. So if we ever need it as a bedroom, that room and the sunroom won't have any privacy!
We loved everything else about the house, and weren't thinking about kids yet, so we ended up buying it. But now, we are TTC and its all I can think about. But we will figure it out when the time comes, since we have no desire to move.