I use Isis Scrap Book cases, which i guess are much like the Art Bin ones referenced above for all my projects. I have one for each project. There is enough room for a layer cake, coordinating yardage, other precuts, thread and the pattern. I can lay a 12.5 inch block flat in the bottom. If a project has any specialty ruler, notions, etc, they go into the bin too. It is easy to take to sew in days.
I have a simple wooden shelf that I bought at Ikea and painted, that holds the bins per shelf, and I have them adjusted to allow me to stack them 5 high per shelf. Don't do the math, you will be able to calculate how many projects I have in various stages. Although most of it is in the idea stage, and not cut.
The bins are $5 each at Michael's in Canada.