Multiple sites, one shared page?

This post could also be called:

• Keeping multisite pages content under single editor?
• Sharing pages through domains?
• Repeating pages through multisites?

I’m trying to find the combination of plugins to have common pages through all the sites in a multi-site installation… or not?
Then I thought it deeply and I found out I would probably not even need multisites at all, since all the sites will be administrated by the same person. No different templates/plugins.

• I can tag pages same as posts.
• I can make permalinks to show like tag/page
• I can map domains to the sub-folders -tags- (can’t I?)
• I can switch a page on/off for each mapped domain just by assigning the tag/category to that page.
• I can add a canonical link to prevent duplciate issues (same page showing in different domains)
• I can even add dynamic variable text in sites like “city” and “branch name” based on the tag/category. This will be a challenge, since I don’t know how categories and tags will behave once they are mapped to another domain. Also I don’t know yet, where to store the branch name (category description?, new table in db? )

My goals are:

• Not having to edit a page 10 times so they look the same, using variable strings if needed to prevent duplicate content and keeping pages personalized.
• Common pages redirecting to main site (by theme or by different navigation menus)

Ideal world would be having all the “possible” pages (services) for each website stored in some common area and just mark them on/off for each domain whether they offer that service or not. (pages should show under each domain, not just redirect to the main site, or I’d just filter them in the navigation menu.

Does it make sense?
Do you see it as possible?
I’d appreciate your comments.