Update: I came by a reasonable alternative to the approach explained below, instead using a GIT repo and a WordPress Multisite plugin: Deploymint: a staging and deployment system for WordPress. ...
I'm trying to set up a WPMU test environment with 5-6K blogs, lots of posts comments, users etc. Browsing trough the WP's functions, I picked up wp_insert_post, wp_insert_comment, ...
Currently I am running a wordpress MU site with ~100 blogs. It's Wordpress MU version 2.8.x Because it was so heavily used, I was asked not to update to Wordpress 3 right away. The users are ...