Željko and I paired today on using xvfb + x11vnc to create a nice and easy setup for running browser tests within the VM while viewing the browser session on the host. I think this setup could be neatly packaged as a MW-Vagrant command that:

1. Can invoke cucumber within a given extension's (or core's) repository.
2. Automatically does bundle install beforehand to ensure dependencies are met (this feature may actually allow us to remove Bundler provisioning from extension/role manifests, achieving a smaller base footprint).
3. Starts an Xvfb process on display :99.
4. Starts an x11vnc process that listens on the host address (10.11.12.13 by default).
5. Opens a viewer on the host. (The best way on OS X is open vnc://10.11.12.13:5900 but is there a Linux and Windows equivalent?)
6. Executes cucumber using the right HEADLESS environment variables to use the already started xvfb session.
7. Outputs the cucumber results to the user's terminal.
8. Shuts down both x11vnc and Xvfb at exit.