Here's the breakdown. Our source, the AppleInsider, had gotten a few tips from people really close to the next "developer build" of Snow Leopard. The tipsters said that it may include a new "Marble" theme. This theme includes a dark transparent menu bar for the windows (Artist's rendition shown above) and a semi-new interface elements and colors for menus, similar to the interface of iTunes. (Artist's rendition shown below). It is uncertain if Apple will release the new UI in the next build. It is certain that we will see it by the time WWDC 09' comes in. (June 8-12, 2009)
***Note that this is only a rumor and that it is not fact until it is released or leaked.
[Source] - AppleInsider:Apple close to unveiling guarded Snow Leopard UI overhaul
