Change layout of the built-in application

Change layout of the built-in application

Is it possible to change the layout of the built-in application of the
Android?
I have Samsung S Duos and I want to change layout of some
application(dialer, SMS messenger and phone book(contacts) are not so
user-friendly for dual SIM cards)
Is it possible to make buttons of this applications bigger or smaller or
to add a new option (sub menu)?
If yes, is there easier way than rewriting and compiling whole Android
source? Or maybe there is an option to change the phone book(contacts) and
reinstall it as a new application?
Any help is appreciated