I agree with Becky's description on an approach to this problem. I usually refer to this type of content in terms of having a "physical location" where you actually created it within SharePoint, and virtual "publishing locations" where you've instructed it to show up by using meta-data. I will add that, when I've implemented similar solutions, it usually snowballs into affecting a few other things. Specifically:

When user's search for content, and a result comes back. Should it link them to the actual storage location  of the content, or should it have a link to each "published" location and hide the physical location completely? You may need to customize the search results XSLT to make this change.
If you need to factor the "published" locations into the navigation of the site, you might need to roll a custom SiteMapProvider that looks at the meta-data to build the navigation using the virtual "published" locations instead of the physical location of the content.
What level you go to really depends on how important it is to hide the actual location of the content from the end user.