Many have asked for this, however it's a terrible (my opinion only) idea. Registry cleaning should never be done blindly. A user should carefully, judiciously and sparingly remove registry entries. While ccleaner is a gentle soul when it comes to registry cleaning, as opposed to competitors, a single mis-removed entry can break a program or even the entire pc (sometimes to the point of needing an entire reinstall).
I've seen programs that will auto-clean the registry but putting blind trust into such a program will typically result into it breaking something, and many target valid Windows settings.