Hi, Colin. VirtualBox has been dropped from jclouds labs as of version 1.9 [1]. We've stopped investing time in virtualization providers such as virtualbox or vsphere as they take inordinate amount of maintenance which displaces our ability to maintain cloud providers. I would look into other products, or the "byon" api, which allows you to use existing provisioned hosts in jclouds, or a cloud provider that works on local vms.
https://github.com/jclouds/jclouds/tree/master/apis/byon -A [1] https://issues.apache.org/jira/browse/JCLOUDS-758