Two of the houses at Hillsdale have dormers, but not sleeping porches. Their dormers are on the third floors of their houses.
For whomever asked about what sleeping porches/dormers look like - when I toured the Chi-O house during recruitment, I remember thinking it looked like the room in the Madeline books, with twelve beds in two straight lines.
Personally, I'm not sure I would have enjoyed that arrangement. We had double rooms and community bathrooms in my sorority house, and I liked that pretty well.