This is the perfect place to put a pull out bed! I always look at those beds and thing they're impractical because it's too hard to leave all of the open floorspace needed for one but I'd happily do it for this library/reading space.
This milk jug reading Igloo was made with 430 milk jugs by @replayrecycled. It took about 4 ppl and five hours to build. It now resides at Down Town Orlando's public Library. This is such a fun craft to make for a class room/library. Kids absolutely love it.