Dynamic VirtualHost Problem - reading from DB or Flat File?

[virtualpsm]

Hello all.  I have been researching dynamic virtualhosts for about a month now and still can't seem to figure out the best solution to my problem. 

Basically, I want to be able to add subdomains & domains to Apache 2.0 dynamically, but I can't figure out how to get them into my VirtualHost. 

I understand apache can dynamically construct vhosts based on the directory structure, but the problem I see there is that I want each site to have the same code base/document root, not read from their individual directories.

I read on apache's docs that mod_rewrite can read in an external file, which may be a possibility.  I would just need to write the corresponding PHP script that would append to or delete from that file when hosts are added/deleted.

Can anyone help me here?  The ideal for me would be to have a directory of flat files (one for each vhost) to read with the vhost information or construct it from my SQL database.  I'm open to all ideas.

Thanks in advance.