DeskScape is an application that will allow you the possibility of using a video as part of your desktop wallpaper. This application is not only WMV and MPEG compatible, it actually presents a new format known as "dream", that adds new possibilities including the option to add theme author information, using event-based triggers to change the wallpaper or the use of dynamic contents.
The trial version provides us with 5 dreams, that is the name that themes designed using this application receive, that you will be able to access from Screen Properties, and you can buy more by visiting Wincustomize. If you want to make your own, you will have to buy the full version of DeskScapes.
For the more innovating users, DeskScapes will become an essential tool to renovate the desktop's appearance and improve their user experience.