I built a bunk over the dinette in my last 1150 and just kept it around when I sold it. Since the floor plan didn't change it still fit perfectly. We actually didn't even use it though as my son slept on the floor and my daughter and her friend slept on the dinette.
With someone my son's size on the bunk I could actually sleep 6 pretty comfortably. Two in the cab over, two on the dinette, one (kid) on the bunk and one person on the floor. And you can still walk to the bathroom at night without stepping on the person on the floor.