Alternative approach to "multiple applications"... is this an issue?

[eluser]hal10001[/eluser]
I've read up on the multiple applications approach touched on in the documentation, but I'm looking more at multiple sites using the same application code base. However, I just wanted to double-check I wasn't missing something because I'm fairly new to CI. My approach is extremely simple. Basically I create several virtual hosts in my Apache config, and point the DocumentRoot all to the same folder containing the CI framework. Then in my config file I change my base url to look like this:

Code:

$config['base_url'] = "http://" . $_SERVER['HTTP_HOST'];

I'm building a CMS, and the display differences, template selection, pages, users, etc., are all driven off the concept of creating sites instead in the admin. Within the admin you designate your base URL for a site, and the model uses this as a foreign key on other tables to pull various content. The biggest concern I can see in the long run is if you have multiple sites with a whole lot of content that you are running off the same database. I have this working conceptually on my dev environment.

Are there other application design concerns I'm missing? Thanks!