Multisite – use one table?

Sorry, not meant to confuse. Here’s what I need, I’m pretty sure it’s similar to what greg wants.

I’ll frame as a user story. Maybe that will help:

As a network admin, I would like to be able to add locations, countries, cities and places as well as any custom post types to the network admin site (the main site on the network) and share these amongst all subsites on the same network. to keep it simple, the option to share should be a switch at the global level (all places, locations etc). This is so I can share one db of content amongst many subsites (on the same multisite install).

As a subsites admin, I would like to login to my own site on the network and on the admin panel only see the ‘places’ and any other custom post type options set up by the network admin (i.e hotels etc). Using these custom post types will allow me to add my own to the global database without being able to edit the original globally shared items or any other site’s items.

As a subsite admin I would also like the ability to choose whether to share custom post type (i.e places) content globally or only on their site. (maybe make this an option that the network admin could enable or disable)

Extra unicorns and rainbows if you gave us:
– The ability for the network admin to give rights to subsite user types (admin, author etc) to edit globally shared content alongside their own would be awesome.
– the subsite admins the ability to choose which countries, regions, and post types to show on their sites.