Open Stack

Its been my understanding that many people are deploying small OpenStack 
instances as a way to share the Hardware owned by their particular team, 
group, or department.  The Keystone instance represents ownership, and 
the identity of the users comes from a corporate LDAP server.

Is there much demand for the following scenarios?

1.  A project team crosses organizational boundaries and has to work 
with VMs in two separate OpenStack instances.  They need to set up a 
network that requires talking to two neutron instances.

2.  One group manages a powerful storage array.  Several OpenStack 
instances need to be able to mount volumes from this array. Sometimes, 
those volumes have to be transferred from VMs running in one instance to 
another.

3.  A group is producing nightly builds.  Part of this is an image 
building system that posts to glance.  Ideally, multiple OpenStack 
instances would be able to pull their images from the same glance.

4. Hadoop ( or some other orchestrated task) requires more resources 
than are in any single OpenStack instance, and needs to allocate 
resources across two or more instances for a single job.


I suspect that these kinds of architectures are becoming more common.  
Can some of the operators validate these assumptions?  Are there other, 
more common cases where Operations need to span multiple clouds which 
would require integration of one Nova server with multiple Cinder, 
Glance, or Neutron  servers managed in other OpenStack instances?