I’ve just modified this original theme created by DevianArt user Lukeedee, you can view the original SnowLion theme here. The reason why I’ve modified the theme slightly is because I don’t like the thin scroll bars, no scroll arrows in Finder (which were a bit buggy), there were a few other things that were changed which you can check yourself, but these are minor things like arrow icons etc.
The things I’ve kept original are the progress bars,, boxed buttons/radio buttons. I added the original arrowed up/down buttons along with the left/right buttons for both options in Preferences (keep together or one at top and bottom). I’ve added a few screenshots so you can see.
My current Desktop.
Finder window. I may change the white back/view bars to grey later on.
System Preferences: Desktop and Screensaver. As you can see, boxed tab buttons.
You install this theme by using ThemePark, which is a free application and easy to use.