I had hoped to have this ready before the Austin summit, but...it didn't happen. Even so, this is the latest big advancement in OVB. It's now possible to do a baremetal-style deployment to OpenStack instances in a completely unmodified OpenStack cloud. Here's video proof: OVB on a stock OpenStack cloud.
I should point out that this is best used for CI-type deployments where an environment is only going to be used once and then rebuilt. The reason is that this relies on an ipxe boot image for each baremetal instance, which means that once you deploy to a VM it can no longer pxe boot anymore. For developer setups, it's still probably better to patch Nova so pxe booting can be handled that way. This is also not documented yet, although hopefully I can remedy that situation in the near future.
As noted in the video, this functionality is not live in the master branch yet because it has backwards compatibility impacts, but it is available in the Github repo on the port-security branch. Theoretically this should allow the use of OVB with real public clouds, although I don't yet know whether there are any that are both new enough (it requires at least Liberty, and possibly newer) and expose all the necessary features for OVB. That will be the next big step, and you can bet I'll have another video when I get it working.