The hideaway bed. This is such a great solution for a shared room with limited play space. The Murphy-bed concept would work so well and the hinged ladder lays flat against the bed making it even more compact.
Simple but so effective. Bathroom door would need to be locked though...for all those ' "Mummy"..."I'm in the bath"..*door opens and in walks small child with deeply unimportant factoid to share* moments'