Openstack - not scoped (http://api.openstack.org/api-ref-image.html)

oVirt - scoped (http://www.ovirt.org/images/e/e3/OVirt-API-CLI-SDK-20111102.pdf)

Openshift - mixed (attributes are scoped to a node called 'data') (https://www.openshift.com/sites/default/files/documents/OpenShift_Online-2.0-REST_API_Guide-en-US_0.pdf)