After living way too long with lumber on the shop floor, I finally rectified that situation. I got the idea from Woodgears.ca to make cantilevered shelves. I was planning to follow the plans, but while making up the lumber shopping list, I discovered Menards has the same thing prefabricated. They might not be quite as strong or smooth, but it sure took less work (and glue and screws) than assembling all that. I bought a few and slapped them up with 2x3's to hang from the floor joists, 2x2s to brace laterally, and one shelf for short pieces and miscellaneous material on the bottom. (By slapped I mean several hours of work and multiple trips to the store, of course.)
I feel much better!
The last photo looks distorted. At least I don't think the entire system is bowed like that.