Emery, Wooley, Morris and Champlain – all on Pembroke – have bathrooms with single toilet and shower that can be locked. One bathroom is shared by 2-3 rooms. AFAIK, these are still freshmen dorms.
This page should help: http://reslife.brown.edu/residence_halls/map.html. Hover over a building and text pops up.
The bathrooms in Keeney are communal and frequently gender-neutral – in that both men and women use them at the same time.
Hope, Littlefield, Perkins are all sophomore dorms now. Miller is now freshman, as is the top floor of Metcalf – no idea what the bathroom situation is there (used to be communal, but they’ve been renovated).