I'd be open to a layout like this -- like the side by side, square shapes and the position behind the bed (good sound blockage from living space and no light seepage from door onto face for person still sleeping).
Built in storage. This is pretty much our attic bedroom! That's a lot of storage and nice touch is the niche for a TV. It may be possible to use IKEA chest drawers to acheive this. Or find a talented carpenter.