Foam Box Shelves/Shelf

A great use for those Styrofoam boxes!
I work at a vet office, and we get supplies in every few weeks and we always have a ton of these Styrofoam boxes, usually before I came along they would just throw them away. Upon this realization I thought "What a waste!?" And started to bring them home, after accumulating several of them, for what I thought would be good packing boxes, and then not moving I had to find uses for them. Well I live with a large group of guys, and being the only girl it gets to be a bit messy for my taste. So I started placing them into shelves I had as 'cubby' boxes and then I started think "Couldn't I make a modern looking book shelf?" So I started playing around with stacking arrangements and here is where it landed me. I placed stick on Velcro between the boxes to keep them together. But now I am wondering if there is a way to mount them on the wall and make them look like they are floating.
Any suggestions or ideas would be appreciated.
As for the lids I use them for paints, and cork boards. :]
If you wanted to you could cover them with fabric, or paint them. I would suggest spray paint.
Happy Crafting!