This is a design for a stowable rack, my flat-pack interpretaion of a cool design by Sebastian Errazuriz <http://www.meetsebastian.com/english/>.
What I think is cool with this concept is that it's flexible, just arrange it in whatever layout or size that suits your needs.
Put them in anywhere you have the extra wall space!
This design has a shelf depth of 181mm (made from P1 sheet), but I'll expand this range to other sizes add design variations too.
P.S. I haven't actually made these yet, but they should be able to hold light to medium weight items. Photos are CG renderings :)