I'm a little late, but just discovered the Wallpaper Engine on steam.
The moving wallpaper selection on there is phenomenal.
After browsing through some of the nature stuff, I thought there must be some incredible A&M ones!...none.
The program has a built in feature for building wallpapers yourself, but I couldn't find a high enough quality video, gif, or picture that would be worth learning how to use the software.
Anyone have something along those lines?
It seems like it'd be really easy to make a moving 12th Man wallpaper if you had the right source material.