We added a 4-shelf closet organizer made by Closet Max:
Cheap at $20, and it folds down for easy storage while travelling. To hang it, I just used a threaded rod covered in 5/16" clear tubing, with nylon locknuts & 1" washers on either side of the ceiling hooks. We'll add extra hanging tabs on the back later on.
However, we were fortunate to already have the hanging hooks present in the ceiling. I imagine someone else can chime in here and advise about installing hooks/brackets in the ceiling. I've seen a few message threads here and on popupportal.com where people have used wire shelving in combination with spring-tensioner shower/closet rods to extend from the top of a counter to the roof, such as here: Galley Shower Rod Shelves
Hope that helps a bit.