Disclosure - EMCer here.
Chris - the VM Volume "advanced prototype" (shown in VSP3205 at VMworld) was a technology preview of this idea, and yeah, it's an important idea, and a disruptive idea.
Anyone who has managed a moderate to large deployment of virtualization knows that the "datastore" construct (on block or NAS storage) is not ideal - as then the properties of that datastore tend to be shared by ALL the things in it. It would be better if the level of granularity was a a VM, but WITHOUT the management scale problem. That's what was shown.
Today, the storage industry (and of course, I personally think that EMC does this more than anyone, and can prove it) are doing all sorts of things to be more integrated (vCenter plugins, making the arrays "aware of VM objects through bottom up vCenter API integration, VASA, VAAI, etc) - but unless something changes, we're stuck with this core problem - VMs are the target object, but LUNs and filesystems kind of "get in the way".
I'm sure that VMware will run it like all the storage programs they have run. The APIs are open, and available to all - but of course, the early work tends to focus on the technology partners supporting the largest number of customers.
More customers use EMC storage with VMware than any other type; and invests more resources and R&D (both by a longshot) - so it's no surprise that the demonstration in the session featured EMC storage so prominently. Pulling something like that is NOT easy, and a lot of people put in a lot of work into it.
For what it's worth - VMware is simply CHANGING what is important to customers and valuable from storage. Certain data services are moving up (policy-driven placement of VMs), certain ones are pushing down (offload of core data movement), and "intelligent pool" models (auto-tiering, dedupe) become more valuable as they map to simpler policy-driven storage use models.
While this was just a technology preview - if it comes to pass - vendors who are able to deliver strong VM Volume implementations, with VM-level policy and automation will become even more valuable.
Just my 2 cents.