Just use the basic tools provided in the content repository.
Publish status and live revision. Its pretty easy to create a page that takes a revision_id and activates any object. There's tcl api's to handle it for you in the content repository.
General comments just does that for the comment objects.
The problem with trying to reuse general comments is, well there are sevaral.
First, it can only be mounted once. Second you need admin over general comments. Third you need to do some contortions to make it work.
If you are building a custom site it is VERY easy to do what you want. I have built a couple of custom sites now where every content object is a subtype of a custom subtype of content revision. This means I can create a custom, site wide UI and api that covers all content in the site.
