Implemented in the 2.1.0 version.
You can use the type parameter to specify the type of Nginx configuration for the site. For example:
sites:
    - map:  landing.local
      to:   /home/vagrant/workspace/landing/public
      type: spa
The default type is phalcon.
If the desired type is not allowed phalcon will be used as fallback.
Available types:
phalcon 
slayer 
proxy 
spa 
silverstripe 
symfony2 
statamic 
laravel 
Feel free to suggest a new type of Nginx configuration
through opening a New Feature Request.
If you change the sites property after provisioning the Phalcon Box, you should re-run vagrant reload --provision
to update the Nginx configuration on the virtual machine.