Apache2 Mass Hosting

The question is valued at 500 points and here is what I need:

I know that a really nice mass-hosting can be organised using mod_rewrite and here is what I need:
1. We've got a file (/etc/vhosts) with this structure:

site1.net                              /home/user2
supersite2.org                      /home/bobby
mysite.de                            /home/anythingelse

so we've got a map with corresponding home dir where we'll find the "docs" folder (that has htdocs meaning) and "cgi-bin"

We're not discussing any log files here

What I need is to configure the apache to:
1. if the request is http://mywebhost.com/users/user2 - then use /home/user2 (if it''s not found - show the default server page - not any vhost)
2. if the request is http://site1.net look for the match in the /etc/vhosts and use /home/user2 (use the default server page if not found)

So I'll need the example part of the httpd.conf that lets me do the things like that for apache2

Hope that it's clear, will clarify if needed