My older two boys share a room and sleep in bunk beds. Since we moved them to bunk beds it's been great as it has opened up a ton of space in their room for quiet time away from the chaos of the rest of the house. I love bunk beds.
two twin beds. A curtain hung from that cute heading would disguise your "bedroom" if you chose. A curtain would work above as well for either a bed or built in shelves and hanging space for your clothing; I really love the idea of deep, built-in beds