A couple months ago I wrote a blog post detailing a microsite implementation we built for a client. The implementation uses a custom site resolver and content-specific configuration to allow new sites to be created and deployed without configuration updates or deployments. That post was picked up by Sitecore’s technical blog, and can be read here: https://www.sitecore.net/learn/blogs/technical-blogs/chris-sulham/posts/2015/01/quick-guide.aspx
My friend Pete, around the same time, released a module that accomplishes this in a more robust way, essentially upgrading the way you manage sites in a Sitecore solution. Pete’s module is worth considering if you need a more holistic solution to site management within Sitecore. Check out Pete’s module on the marketplace, and the source on GitHub.