Now many people not willing give up iOS 6 to update an unstable iOS 7, because it is still in the beta stage, exists bugs and instability. Moreover, they can get the untethered jailbreak on iOS 6. But we have to admit that the new system interface is really pretty. If your device jailbroken on iOS 6, then you can change the system appearance with cydia tweaks.
We have talked about how to install some jailbreak themes and tweaks to make a jailbroken iPhone looks like running iOS 7. Such as lock screen, icons, system framework, Notification Center, status bar, messages and dail pad. You can search all those themes from Cydia Store for free. However, there are few themes for iPad.
Now iOS 7 lock screen theme available for iPad at Cydia BigBoss Repo for free, you can also change the wallpaper simply use iFile and replace LockBackground.png to whatever wallpaper you want with the same name.
If you want to change other iOS 6 elements, just search iOS 7 & iPad related tweaks in Cydia.
iOS 7 Lockscreen iPad Theme
Color Messages iOS 7 Themes
iOS 7 Bars And Battery
iOS 7 Font
iOS 7 Icons for iPad
iOS 7 Keyboard Pack
iOS 7 iPad Theme
You can find above themes from Modmyi & BigBoss Repos, just search iOS 7 in Cydia Search Page.