379770 USI Web Based System

I would like a web-based system to be built in PHP or using an OpenSource CMS (Joomla or Drupal or any other recommended by coder). This website will have Home, About Us, Services, Safety, Careers, Contact as it's major categories and within it, it will have links to other pages. Approximate number of internal pages will be around 40. Furthermore, the web-based system will have a "Member/Employee Login" where employees can submit/search/delete/update there Timesheets. Needless to say, GUI should be shown to user according to there credentials (May be saved in OpenLDAP or some open source LDAP...suggestions welcome from programmers). The web-based system should use some sort of structured programming, such as a Design pattern (Ex: MVC) (Other suggestions welcome from programmers). In future, this system can even be expanded (Which will mimic an in-house application, built with Access and MySQL backend. All the database tables along with CVS will be provided to the coder for this expansion). Hence, initial Website/Employee Login system should be efficient/maintainable/scalable to include a bigger system and should not be considered as "Just a Website".