Windows Phone Hacker, the developer behind the Folders homebrew app, has come up with a new concept to add small tiles to the lock screen that can display app information, much like you'd expect on the home screen live tiles. Data could be pulled from apps such as weather, RSS readers, image sharing, etc.
Another idea is to have the wallpaper dynamically change to fit the Bing background. The bad news is you'll require root access to be able to use this app, should it become reality of course. Be sure to head over to Windows Phone Hacker to spark interest in the concept.
Source: Windows Phone Hacker