Have you ever considered painting plastic but are unsure if the paint will actually adhere to a smooth surface? The good news is that you can paint plastic. Your basic plastic items can be personalized with a fun and unique color. Here are the steps to take in order to paint plastic.
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.