I haven't seen this one mentioned before.
say we have several working sites with the following base urls
example.com/
example.com/red
example.com/green
example.com/yellow
example.com/blue
using custom settings.php files in the sites/ directory and distinct themes by placing themes in sites/sitename/themes, we have several customized sites.
PROBLEM:
we want to manage the example.com/red, example.com/green, example.com/yellow, example.com/blue *content* from the "master" site located at 'example.com/'.
we're sharing all tables, but we want to target node entries to specific sites. for example. we want an about page for each site. so from our master site we create 4 different about pages and for each of these pages, we specify one of the subsites. each subsite then displays the appropriate about page.
for any piece of content created, we want the ability to display it on none, some, or all of the subsites.
ideally we will completely turn off the admin interfaces for the subsites and manage them exclusively with the files in the sites/ dir (where we'll specify site details/settings) AND our master site (where we'll generate content for the subsites).
it seems to me that i might do this by adding a custom field to all content input forms using 'hook_?' and then applying a filter to all requests for content using hook_filter.
i can't believe i'm the first one to come upon this problem.