Great for a guest room especially when you use the closet for storage...hang rod and shelf, then hang a robe there with extra hangers so people know what it is for. Then get a suit case rest for underneath it.
What?!?! build a play area/loft above the bed. Include bookshelves behind the bed and drawers under it. The only thing that would NEVER happen in this room is TWO boys - one would push the other through or off the top while wrestling and that would be the end of the "good" idea.