Pull out Wardrobe Rail for under stairs. You could have a few of these attached under the higher stairs and some storage boxes or even a chest of drawers underneath, then you could do away with the black frame and the room would look / be much larger.
Drawer runners & Drawer slides - Pull Out Wardrobe Storage
Decoration, Innovative Sliding Storage Under Stairs With White Walk In Closet And Wooden Stair. Could be great for storing coats out of sight!
Decoration: Innovative Sliding Storage Under Stairs With White Walk In Closet And Wooden Stair. Office Storage, Toy Storage Solutions, Interior Design Ideas For Stairs, Camping Storage Solutions, Home Staircase. Remarkable Storage Under Stairs Decorations And Pictures