Hummm, let me try to explain it better...
Today I have a single Wordpress MU hosting 50 blogs in a common domain, let's say: http://blogs.example.com. My installation mode is per sub-dir, so the blogs are:
http://blogs.example.com/person/
http://blogs.example.com/blogtest/
http://blogs.example.com/theone/
and so on.
Now I have a demand here, instead of using the blogs on this domain, I need to "map" each blog to a different domain, organized on a sub-dir structure "per subject". Examples:
http://news.example.com/sports/person/
(Was: http://blogs.example.com/person/, the content of this blog is mainly news, about 'sports', hence the new url)
http://news.example.com/global/blogtest/
(Was: http://blogs.example.com/blogtest/, the content of this blog is mainly news, about global facts, hence the new url)
http://entertainment.example.com/theone/
(Was: http://blogs.example.com/theone/, the content of this blog is mainly entertainment, hence the new url, but now without a 'category' sub-dir).
Each one of these new "mapped domains" are the root of the blog. I can accomplish this installing separate instances of Wordpress, but this would kill the main Wordpress MU advantage (multiple users for multiple blogs in a single installation).
When I edit the blogs, there's an option for each one of the blogs, to change the "Domain" and "Path" URL location of a blog. It also sets home and site_url on the database. This change isn't working like I said before...
I think it's a limitation of Wordpress, and that's because I'm trying to gather information about it. Maybe I'll need some type of customization like the domain mapping plugin, but instead of mapping to a specific domain, I have to map to a specific domain *AND* sub-directory (not limited by number of sub-dirs, like I said in the examples).
Hummm, I think I made it more clear, if not please say and I will be glad to explain more :)