Rapid Site Deployment (database Driven Domain Name Server (DNS) + Apache Config)

I am trying to do something that I believe is fairly non-standard. What I am looking to do is create a system where I can rapidly deploy web sites without having to restart named and Apache. For example, if a customer completes a process, I want to be able to turn that site on immediately using a temporary domain (somecompany.example.com or othercompany.example.com).

With some programming language (hopefully PHP) I would like to get the customer up and running with their site immediately without having to restart the server. While doing some research I found I could use MyDNS which uses MySQL to manage DNS data instead of configuration files. MyDNS can be updated on the fly.

For Apache I have seen wildcard configurations, but everyone seems to be suggesting the use of mod rewrite. I would prefer that the domain maps directly to a specific folder:

somecompany.example.com -> /sites/somecompany/htdocs
(*.example.com -> /sites/*/htdocs)

Does anyone know how I might do this with Apache. It seems similar to user directories (example.com/~username -> /home/*/htdocs)