While reading one of my favorite blogs, Unclutterer (it actually calms me... is that weird?), I came across this great nesting bookcase from Dror. It can be used in whatever way suits you best, with as many stacks as you want to add, and you could even arrange the individual pieces to be end tables. If you find yourself moving from apartment to apartment often, these would also be easy to pack up and transport to a new place.
These are available at Target (but currently out of stock); four open shelves are included in each package.