Well, I am jailbroken and haven't been able to find a theme for it. And just taking a picture of the battery won't work, because unlike the lockscreen when its charging, the battery would never update its charge and just remain a static image.
I would like to know if there was a way to take the dynamically changing battery from the charging lockscreen and implement it so that it will constantly display as my lockscreen, not only when the phone is charging.