I have a collection of strongly related websites for book publishing. A couple of news sites and some basic publisher sites. They are all wordpress sites with different frequency of updates but I end up doing a lot of posts that are nearly duplicates across them and easily could be identical.
The problem I would like to solve is, one central repository for posts and then have each site act as a view of the total set of posts with some mechanism (Categories?) for selecting which posts are displayed on that site (An one kitchen sink site that has everything). I am not committed any particular solution and am trying to describe the problem as generically as possible to keep options open. It needs to run on a linux server, apache with a mysql backend, other than that I think I am wide open (Oddball apache plugins might be an issue).
Ideally each site should have the one set of posts to draw from but its own theme (and possibly plugins).
Currently the sites are on separate domains (Multisite doesn't support this AFAICS), which is nice but not essential to keep.