Our pals over at domino magazine have a trifecta of DIY projects for the shoe enthusiast; the do-it-yourself shoe racks come in beginner, intermediate and advanced varieties -- enough assortment to fit anyone's inventory.
While none of the instructions are explicitly "green" in nature, we really like DIY projects because they allow you to go as green as you want. When you need a modified bookcase, go second hand; when they call for paint, go low- or no-VOC, and you'll be greener for your efforts.
Having so many shoes that you need a separate shoe rack ain't that green, but if you're going to need one, might as well make it as green as possible. Pictured above is the "beginner" repurposed bookcase; hit the jump to see the intermediate and advanced varieties. ::domino magazine DIY: Build Your Own Shoe Rack
"Intermediate": Demi closet
"Advanced": Shoe Built-In