If you’re looking to customize your iOS 7 app switcher, you should know that MusicalSwitcher turns it into a piano. Once you install the tweak, you can swipe down on any app card to produce a note and scroll to the right to climb the scale.
You can also customize the tweak, but that requires a bit of manual labor. You can create your own sounds in .m4a format and via SSH navigate to /Library/MusicalSwitcher and replace the existing sounds with your own ( but make sure your files have the same name as the existing files ).
MusicalSwitcher is available for free in Cydia via BigBoss repo…