My roommate and I built our own in Harper freshman year and it did make more space, but I am still not sure how that thing didn't collapse and kill me since I was on the bottom. We also had 3 guys in a 10x12 room, they have since stopped doing that, so we were desparate for more space.
We lofted our three beds in an HSS corner room. That gave us room for a futon couch and a loveseat/hide-a-bed. So we had quite a bit of space to work with.