Cubicle shelving ideas?

I’m running out of space in my cubicle, particularly for my toys. Right now their lining the cubicle walls, so I need another level down, more or less, to make room for new arrivals.

We can’t do any kind of drilling or anything that would make hanging an actual shelf easy, so I was thinking about a free standing shelf. The problem is, anything high enough is too deep, when I only need it to be about 3 inches. Also there are things like outlets that need to be exposed on the cubicle walls, so the shelf can’t be blocking that.

Instead of actual shelving, I was thinking about making my own with something like Construx or K’Nex. Construx are apparently pretty old school and hard to find, but I thought they would be good because of their plating. K’Nex seem to still be around but don’t seem to cater to well to making a flat surface for sticking things on. Of course I could always just use them as a base and place something flat on top.

Any other ideas or suggestions?