Is it possible to deploy the OpenStack bundle to one machine with the CLI?
Is it possible to edit the example.yaml bundle with --to machine?
If yes, how?
You would need to modify the bundles .yaml file to include the 'to' directives, I don't have any experience with deploying the Openstack bundle specifically to a single machine however.
An example using 'to':
You can find more information on the deployer here: http://pythonhosted.org/juju-deployer/config.html#placement
Additional information on deploying bundles from the CLI and the GUI can be found here: https://juju.ubuntu.com/docs/charms-bundles.html
You can install openstack-in-a-box using DevStack.
It is not a production setup, but it is pretty easy to install and get up and running from the CLI.