When we bought this house, we knew we could fit the 10 of us who would be here full-time into rooms. There are 3 bedrooms on the upstairs part--the master, which is pretty small for a master bedroom, a bedroom that's almost as big that the 3 girls are in, and a pretty small one for Micah, Drew, and Verity. There's one small room in the basement that Caleb and Jonathan are in with no extra room.
That just left Nathan and Luke. They're not going to be here all the time, but they are here sometime, and we wanted them to have a place to stay that wasn't just out in the open, like on the futon in our lego/TV/treadmill room downstairs. There was one last space--a tiny narrow sort of mudroom area where the basement door outside was, as well as the door into the utility room. We measured, and it looked like we could (barely) fit a set of skinny bunkbeds in. Fortunately my parents had an old metal set in their basement, and they were even more perfect because the ladder was on the end. As I'm sure you can see, there would not have been room for a ladder on the side!
I'm standing in the doorway to the basement hallway, and the wall to my right goes several feet until in turns in a few inches, and there is the door to the utility room. The only outlet in the entire room is halfway up that wall, guaranteeing that anyone trying to slide by the bed will knock out anything plugged in there! We put an extension cord there so at least the boys could charge their phones by their beds on that tiny bookcase.
We also realized we could (barely) fit in a dresser at the end of the bed. We went out to the garage, where we had 3 extra dressers, and we uncovered and dragged out the smallest of the 3 (no small feat in and of itself!). At least it gave them a place to put some of their stuff over Christmas break. We hung an over-the-door closet bar on the door to the utility room (facing into the utility room) for their hanging clothes. Fortunately there weren't many of them! We also put an over-the-door towel hanger on the back of the door too the hallway for a towel.
So the room worked, although it was pretty cheerless and crowded. At least it has a door so the little kids didn't wake them up in the mornings! I call it "the cell" because it looks vaguely prison-like, or at least what a monk might have in a monastery. I'm sure the people from whom we bought the house had no idea that space could or would ever be used as any sort of a bedroom!