We recently completed this project for two girls and their parents, on the Upper East Side. Over 14' wide double loft, with a small cubby staircase going up to a passageway in the middle. Two matching desks, too. Railing in a chestnut oak, whitewashed.
We just acquired some handsome pieces of weathered, smoothed, fresh-water driftwood, dried on the banks of the Neversink Reservoir, upstate in the Catskills. Could be great posts, columns, rails, or balusters for your next loft bed. Could be stained, oiled, or painted.