a cool product side
I clicked on a google ad at that shoe-storage idea (NotMartha.com)
and found this:
One of the things I hate about all the plastic storage boxes is that the lids nest, and you can pull out the one in the middle. I have a set of food-storage boxes I use for my sewing stuff, and my mom and I both love them bcs they have side rails for no FRONT rails (on the lids). So I can pull the middle one out of the stack without having to lift anything up.
And these guys have latched on to this: "Ordinary containers stack one on top of each other. If you need a lower one you must unstack others to get at them but not with our patented design! Individualy containers can be pulled completely OUT for easy access with out the rest collapsing or having to unstack."
The difference for THESE is that the stack stays in place--the hole in the middle stays in the same exact spot, the stack doesn't fall down a notch.
I'm going to have to look into these; I have no idea how expensive they are, but it's an interesting idea.