I love the idea of building the bed into the structure of the room for children's rooms. Beds are large pieces of furniture and take up space. This allows for more floor space. I would make the bed into a bunk bed for both Laura and Hannah!
Built-in bunk beds is a great idea to preserve space. The built-in book shelves also help to create more storage for toys, books and etc. The first step of the ladder has been eliminated in order to add under bed storage/trundle.