Multiple wordpress sites using the same files?

Hi.
I want to automate the creation process. My idea is:

1- the client creates an account in my site
2- I confirms this account and creates one wordpress instalation to my client.
3- The client logs into the admin area and chooses one pre-fixed theme and fills the wordpress with content.

Ok. My doubts are related with the file structure to this project.

If I have 5 clients, can I use 5 different sql tables connected to just one wordpress archives directory?

See that would be 5 different sites with different themes and different databases using the same files.