This organizer is fabricated out of some heavy-duty (1/16") wood-grain paperboard that I found, though other materials (thin plywood, cardboard, corroplast) could be substituted. A pair of suitable hinges are made (in my case, scored creases) so that the three panels of the organizer can fold.
The clips are "mini binder clips", which are pretty cheap (about 1 USD per dozen). After laying out their locations and cleaning off any manufacturing oils with rubbing alcohol or similar solvent, simply swing one leg back, apply a dab of epoxy to the board, and press the clip down, securing the sheet metal body and wire leg. A close-up of this position is included.
The organizer pictured is 30" tall. It couldn't be much shorter, because the center panel is designed to hold both a 11" by 17" and a 8.5" x 11" piece of paper, with a 2 cm distance between the top of the panel and the top of the top binder clip, and a 1 cm distance between the bottom of the 17" tall piece of paper and the clip below it.
This panel is divided into three panels; left to right, these are 9.5", 12", and 9.5" wide - slightly wider than the paper each panel is designed to accommodate. This is important; if the panels are narrower than the paper, the paper will be creased each time you fold up the organizer.
The clips are arranged so that three sheets can be stored on each side panel; separation between the two top clips is 2".