I'd like to create and test a service that permit users to register and create a single page, then this single page will be accessible by 3rd level domain.

I thought that I can use couch with members module and databound, but I need help or hint to restrict users so a single user can create only one page (and edit the single page that the user create). Then I need to connect 3rd level domain to the correct single page...

Can be done with couch? Or better if I start from scratch?