Love this play area over the bed, like the anti-loft bed. I think I& leave off the first couple of steps of the ladder and make it a safer place for the older kids to play with and store their LEGO creations. (Apartment Therapy with loft bed inspiration)
This is another example of a layout that would be easy to install in a studio apartment - a loft bed with stairs would be a cheaper and nicer space saving solution than buying a Murphy bed. Maybe even in a small bedroom.