Bunk bed cubbies: could build a box for the bunk beds, curtain over each cubby. (leave out the TV that is in the bed in the picture- kids do not need to watch TV in bed). Could build something similar for a reading nook instead of sleeping area.
Complete DIY guide on how to build a loft bed. Basically a box on top of 4 posts with two twin beds pushed together on top. Such a cute kids room idea to save space :). ( girls room with a bed underneath also )
Increíbles literas que te ahorrarían muchas peleas con tu hermana