You can try checking out
hopkins cribs. A&B's rooms are slightly larger than the AMR rooms, so they'd probably hold three people better.
Plus, I got to take a look inside the triple. It was arranged so that two of the beds were lofted and the people had their desks underneath their beds, and the other one was on the other side of the room. It didn't seem particularly spacious, but definitely big enough to hold three people in a dorm room.
...uh.