Advice regarding site architecture

Hi!

I would like to have some advice on what would be the best way to set up portion of a site. We have a situation where we have a number of pages (let’s say “Departments”) and each one of them has subpages structured exactly the same way. So, for example:

— Page 1
— Departments
—— Department 1
——— Introduction
——— Description
——— Materials
—— Department 2
——— Introduction
——— Description
——— Materials
—— …
—— Department 20
——— Introduction
——— Description
——— Materials
— Page 3
— Page 4

What I’m interested in is what would be the cleanest way to set up the Departments section. I’ve come up with two solutions thus far:

1. Just create them as regular pages
This would be the easiest and most compatible, fool-proof way (regarding plugins), but would require manually setting up 20×5 pages and would altogether result in more than 100 pages in the database — can WP handle this without problems? We’ll be also using a cache plugin. The manual work on initial setup wouldn’t be much of a problem as we do not need to add new “departments” regularly. Yet, setting up pages with the same titles 20 times seems slightly counter-intuitive.

2. Create “Departments” as a custom post type, make a post for each department, add subpages content as custom fields and build a custom template file to display subpages.
This option would be the easiest to manage content-wise, but raises many concerns regarding plugins compatibility (WPML, cache, …), building site menus etc. And I’m yet again concerned about performance, as we already have quite some custom post types set up.

Both options would do the trick, but which would you prefer? Perhaps there is a third or even fourth option we haven’t thought of?