Sorry, I always come up with crazy ideas, but: When my boys were little, I made bunkbeds out of 6"x1"(?) redwood. The bottom was not attached, therefore the top was like a loft. The rail that held the mattress in the bottom part of the loft section was attached to the wall on the wall side. It had plywood to hold the mattress in. Kind of hard to describe, but the point I am trying to make is that the mattress was up off the floor, so there was space underneath for a bed or a desk, or whatever. Wish I had that "loft" now, as it would be a good place for storage, fabric, etc. You might google bunk beds and get an idea as to what I am trying to explain.