I do not know if this is brand new, but it was just recently featured on MacBreak. It is called TransparentDock and it allows you to change the dock's background, inner and outer boarder, and several other animation features. It gave me the ability to pick anyone of about 15 colors and then allowed me to set the opacity. I like that you are able to specify the color of the boarder independently of the background. Best buying tip of all, it was free. Here's are two screenshots 1. a pic with my current desktop, which is cool because it allows the dock to look completely transparent, which was the second dock style I almost went with, but still allows me to have the context when placed against a different backdrop; 2. with a white background for context because as you can see from my first shot the desktop is black. Anyway, enjoy!