Did you buy your iMac before they released the latest generation? If so, you're probably looking at the new metal cases with envy. Don't worry though, thanks to Chromac, you can have a metal iMac without the need to upgrade.
The Chromatic iColor is a line of enclosures for the previous-generation of iMacs. They come in 11 different colors and materials. These include 24K gold, platinum, and plain colors like lime green.
Honestly, I wouldn't waste my money with something like this. First, they're really ugly. I think they make your iMac look like a cheap knock-off. Then you have the price, they start at $500, but you'll pay more for having gold or platinum. Save your money and just buy a new computer.
Chromac introduces upscale iMac enclosures [via slipperybrick]