I want to thank you for the reply, it really clarified things. I understand most of your reply but wanted to think it over and ask some more relevant questions (I hope)
First, I appreciate your first 5 steps. This is roughly what I had in mind. On step 2 I figured that the template pages would have php hooks to the database instead of storing the entire template. This seems more straight forward and should be simpler and faster to code, and easier in terms of database design. Step 4 (registration) should be a little bit easier to implement because I am intending on free registration.
I really appreciate your bringing up step 7. I didn't consider mobile devices at all and will have to address that. I am not sure I understand "CSS media queries" but targeted styles would allow for display, right?
I don't really understand step 6. Wouldn't each user get one site based on their registration?
Further, what about attempting to do this with a CMS? Is this just wrong headed? I am really unclear about whether or not this would be easier with a CMS and if so, how it would fit together.
Thanks ahead for further clarification,