Multisite vs multiblog

I am confused about the multisite concept as implemented in WordPress. When I create a new site in my multisite installation, I don’t get a new entry in the wp_site table, I get a new entry in the wp_blogs table. Each blog has the same site_id but a different blog_id. From this I understand that “multisite” really means “multiblog”.

Now, each new blog has a set of tables with names starting with ‘wp_’ + blog_id, except my first site, which has a set of tables with names starting with ‘wp_’. I suppose that’s because WP has to be installed first in the single-site version, where the table names start with ‘wp_’, and the table names don’t get changed when installing the multisite version on top of the single-site version. However, it makes things a little hard to work with if I want to construct dynamic queries using the tables of different blogs, since the original site has blog_id 1. It seems that if we wanted to set up options for the entire network of blogs, they would go in a table wp_options, but that is in fact the options table for the first blog.

When looking at my wp_2_options table, I see it has a column for blog_id, which suggests that this really is a site that could contain multiple blogs, rather than a blog. However, blog_id is always set to 0. Why not just use a single table, wp_options, for all the blogs, and make use of the blog_id column to indicate which blog the option is for? Well, that’s because wp_options, in accordance with the table-naming convention, applies only to the first blog, rather than to the entire network of blogs.

Ultimately, what I want to do is have a network of multiple sites, each containing multiple blogs. It looks like perhaps this was the idea behind the multisite implementation, but that it wasn’t carried through with an appropriate database schema, and all we can have is a site with multiple blogs. That means that I would need to set up multiple installations of WordPress for each site, and use the multisite installation to have multiple blogs on each site. Unfortunately, then there’s no easy way for all the installations to share a single set of users, for instance.

Is there a way to do this that I’ve overlooked? Thank you.