I've been asked to spec-out a site using Drupal for a large client. Said client is considering Drupal as one of 3 alternatives for a large setup. Unfortunately this is just preliminary at this point so I don't have all the details, but the main catch is that they want to have separate suborgs within the organization. I'm not certain at the moment how separate they want each of these suborgs to be, but they do want them to be able to each have their own news/events information as well as having the ability to share news/events with other suborgs/the main organization, as well as with outside systems. That means both suborg-specific calendars and organization-wide calendars. They also want selected employees in each suborg to be able to post personal blogs, as well as have lists of people in different positions (which may or may not map 1:1 with users). I'm not sure if each suborg needs its own theme, but I'm pretty sure it does. We need to be able to scale to about 50 suborgs eventually. They like the RSS buzzword and want it all over the place. :-)
I know that information is still a bit thin, but it's all I know at the moment. :-( Hopefully I'll add more when I learn more.
So far I've identified a couple of different ways to go about this, and I'd like some input on what could be stumbling blocks with each.
1) Organic Groups. Each suborg is its own OG. I'd theme OG to not show a news ticker on its front page (or not, depending on whether they like that or not), and the admin of each suborg would be made the owner (or maybe just an admin) of that group. og_calendar handles the suborg-specific calendars from event module. Each suborg admin is instructed to be careful with his node paths to make sure they fall in the right place. :-)