A new bed for David's room. He asked for a shelf above the bed as well to put books and a clamp reading light above the bed. Maybe extend the end of the bed for extra storage? Might make the bed a bit taller as well to make room for his Lego bins.
minimal stairs, not exactly like this but space saving Simple Staircase in Belgium Mini House. These stairs take up very little space thanks to a pivoting design with a (very) small platform at the bend.