I have the same problem. I use 4 of the Smead Retrospect expanding files. You will have to Google them as this site no longer has them but they are out there. They are made of heavy plastic, have about 26 storage sections, easily handle 12 X 12 papers, and have a sturdy carry handle. The dividers are tabbed so you can easily label them. I put different kinds of paper into each: 1 for patterned papers, 1 for neutral colors, 1 for solid colors including textures, and 1 for vellums, metallics and miscellaneous. They are easily stashed in a closet or cupboard, under a desk or bed or wherever. It would be nice to have a whole room, well organized, with lots of shelving, racks and drawers, but it's never going to happen. I have these paper cases, a work table, a few shelves and a ScrapRack which isn't even in the same room and this has worked out pretty well. I hope you find a good solution too.
I have a bunch of plastic boxes that look like rectangular briefcases and open up the same way. I bought them at a national chain crafts store. They are see through and made specifically to fit 12 x 12 scrapbook paper. I have all of my single sheets in there. But it can also fit like 2 or 3 stacks. I love them because the paper doesn't get ruined and they're easy to carry. I even have a couple for my stamps!
Very interesting forum discussions. In Brazil, where I live, many people search sites to find special products for scrapbook making, including among roles to scrapbook and custom punches. I know a site in Brazil that has products for scrapbook. Not be useful to you why you are in Portuguese, but the pictures of scrapbook materials for help.
Have you searched the gallery for pictures of scrapbook spaces?? Maybe something there will catch your eye. I'm not sure what to do if you don't have much vertical OR horizontal space. The one 12x12 (approx size) cube from Michael's will hold quite a few papers. You can get one that has 3 spacers in it that will divide some of your papers. I have never filled one completely full nor have I counted the paper after loading the cube, but, if I was to guess I would say 1 would hold 500 papers?? Maybe more.
I have the collapsible paper tower tote, it is full to bursting with paper, I have one of the cubes from Michael's, it is full, and I have 3 of the double deep Iris cases, all full. I think I have too much paper, lol!
I have quite a few Iris tubs, too. They stack nicely. The last time I was at Costco.. they had a brand that was similar but had tabs to open/close that are much easier on my arthritis than the Iris ones. They were very bright and cheerful colors.
I've had several different methods of storing my paper through the years and have never been completely happy with any of them. I'm currently using plastic storage bins that I've found at M's and HL that are tall and thin. They have a lid and come with three hanging files in them that hang inside the bin. You can buy packs of additional hanging files to go in them. Each file holds quite a bit of paper. The bins have a lid. Because they are tall and thin they stack well and don't take up too much space. I can also put them under my table. Wish I could post a picture of the product, but they don't seem to sell them at SB.com! I currently have my paper sorted by brand - one brand per file with a few files that hold specialty paper like Christmas and Halloween. I'm finding this to be a good system for me. I like having the brands together. For me it makes it a little easier to mix and match. I also like having my paper in a container that has a lid. It keeps out the sunlight and dust and I just feel like my paper is a little more protected.