Sure you can... have you tried training-labs? It installs OpenStack following the official install guide, and the default setup is VirtualBox.

http://docs.openstack.org/training_labs/

MaaS is cool, but you don't really need it for your plan. You can just install VirtualBox in all the machines and after you are good with the All-In-One setup, just migrate the VMs to the new servers and edit the VirtualBox networks to be bridged.

If you are planning on extending your infrastructure, you probably also start expecting some performance... So, with not much more effort, you can use the same method and install with the "KVM" driver of the osbash installer.

By the way... with training-labs you can now also install the nodes via PXE, similar to MaaS and Autopilot, but well... not for big production environments.