Backup Individual Users && Blogs

Hi, I have extensively searched all forum topics here and on google but I cannot find solution to this.

Version: Wordpress Multisite 3.0.1

What I want to achieve ?
I would like to backup all user lists and their blogs (except admin) and restore them to a fresh WP multiuser website. In this way I will be able to clear 2 years of clutter by complete removal / reinstall of WPMU and all my users will be able to access their blogs without any problem.

How to do this ?
I think this would be possible by backing up
a.) Every individual blogs tables (excluding wp_1) - around 600 blogs.
b.) Blogs table
c.) Users table

I am not really sure what tables need to be backed up and how to do it via PHPMyAdmin. I am also not sure about how to restore all these tables in a fresh WP multiuser website. Any guidance will be highly appreciated.