Bunkroom basement. What an awesome idea! I've always said if I win the HGTV dream house I'd make part of it into a bed and breakfast/place for teenage groups to stay and this is one more idea for maximizing the rental space.
Our home doesn't have an attic, but we looked at so many that we thought couldn't be finished because of the drop down. This is just plain cool, and what we will do if we ever do buy a homee with this sort of space.