I'd like to know more about what it means to you (and to your colleagues) to "represent" those services. There are 2 ways to go here - representing the services of those offices within existing courses, or representing their offices as courses (which is what you're currently doing).
In my opinion, the Moodle-as-Intranet idea works poorly. We rely on MyMoodle heavily, and do not encourage people to go browsing for courses, so an office Moodle page isn't easily findable. (YMMV.) The big question, to me, is what specific Moodle tools these offices want to use. If there isn't an answer (or if there are other tools available which could accomplish the job), maybe it's not a good fit.
We've had a little bit of luck with library resource metacourses - any student in any Psychology class can see the Psychology resource page. I'm still of mixed mind on this solution. On the one hand, it does show up as a Moodle resource when the student logs in, and the student is the primary audience. On the other hand, it's hidden to students/faculty/librarians doing interdisciplinary work in other departments. This has led the librarians to generally prefer their own CMS.
On the other hand, there are a number of approaches to embedding student services within a Moodle page. A lot of people have worked on library blocks, for example. You can do a heck of a lot with a simple HTML block or an RSS block - I could imagine providing blocks for advising, services to students with disabilities, the writing center, etc. It might be more useful for students to see the services as an integral part of their course page instead of a separate thing.
For that matter, there's no technical reason that librarians, advising, and student life staff can't have appropriate access to Moodle pages. (There may be policy and local culture reasons.) If it would help those offices provide services more effectively, you could embed them in the course with appropriate permissions. We've done this with great success with library services.