If you are a crack flasher like me who loves to flash Roms and other Mods to your Android device, chances are you have often wondered about creating a theme or custom mod yourself. Or maybe you have wondered how to go into your system and change a few things here and there to customize your device. One of the easiest mods to make on your phone is the Dropdown Notification background. You can simply modify the image using ninjamorph. There are several other theming mods that you can make via Ninjamorph. You can mod anything having to do with the notification menu and anything having to do with the dropdown and more! You can use any image from the web, you will have to resize it to fit the background, or you could use photoshop to make your own background image. The method is simple. Just unpack the Framework-res.apk in ninjamorph and replace the notification background png. Then repackage the Framework-res.apk. The process may take you a bit of time the first time you do it, but once you become familiar with the framework-res.apk you will be able to mod all kinds of stuff with ease! I would highly recommend that you make a nandroid backup first incase you accidentally change something that you shouldn't have.
Detailed instructions here