vHost Configuration per DB?

Is tat possible?

I mean a dynamic Virtual Host, that gets its data (docroot, user, group,
serveradmin) from a mysql DB, depending on the requested hostname...

This would be GREAT for MASS Hosting... My Apache is very fat and slow
with 500 Virtual Hosts, so how can I avoid this? I am aware of
mod_vhost_alias, but that would not work because I have a SuEXEC
environment, which means I need a seperate User for each vHost.

Any hints appreciated!

Regards
Mario