I like this idea, but I think the "step" shelves need some more support. Garage shelving idea: the lower shelves actually glide out so you can step to reach top shelved items. Then they slide back to the wall.
Build these handy undersink roll-out trays in a weekend. You can tackle this project with simple carpentry tools and some careful measuring. You can make all the trays in an afternoon using building products from your local home center or hardware store