Another creative idea for small beds is the bed hut above. If you do not have a lot of room for a spare bedroom or a master bedroom, a bedstead can sleep without taking up more space than the bed itself.
By simply placing a large bed in an alcove, you create a small bed hut. A necessary feature, however, is some sort of way for anyone sleeping there to add some privacy. A simple curtain allows this intimacy. So that the space is not so narrow, it is also a good idea to try to have the bed corner near a window.