You don't need 4U chassis for video cards.

http://www.dell.com/content/products...=04&l=en&s=bsd

2U chassis with dual video cards in a rack mount. Course if your building your own your mileage may vary. If all your wanting to do is buy a rack to put your boxes in. That's fine. Just get some rack shelves. and stack them in there on their sides and stuff. No special hardware needed and your clutter will disappear. Even a cheap bookshelf can be used as a "rack".