HowTo create a System Default Dock on Os X

  1. Create a standard user account
  2. Login as this user
  3. Personalize the Dock
  4. Logout
  5. Login with an account that has administrative rights
  6. Open a terminal window
  7. Execute these commands:
    sudo cp /Users/<user you used at point 2>/Library/Preferences/com.apple.dock.plist /System/Library/User\ Template/English.lproj/Library/Preferences
    sudo chmod 600 /System/Library/User Template/English.lproj/Library/Preferences/com.apple.dock.plist

From now all the new accounts created will use this standard Dock as default.