Create real estate property pages with unique urls?

I am looking for a solution that will allow me to map a domain to a page within a wordpress site.

I have a client who wants to create one-page real estate listing pages and have each page with it's own domain or sub-domain. So, for example, his site is http://www.joesmith.com and he has a property at 123 Anystreet, Atlanta, GA. He would like to either create http://www.123anystreetatlanta.com, or be able to create http://123anystreetatlanta.joesmithe.com.

For each property, I will create a custom post type so he can choose a page template and deploy the page.

Do you have any thoughts on the best way to approach this in Wordpress?