Looks like Alex Freedland's recent prediction that OpenStack Will Eat IaaS AND PaaS Vendors could be coming true. Just last week, Rackspace, one of the founders of OpenStack and a primary steward of many of its projects, announced Project Solum.
Here are the areas that Solum plans to address:
2) Ease of application lifecycle management across dev, test, and production types of environments -- supported by the Heat project’s automated orchestration (resource deployment, monitoring-based self-healing, auto-scaling, etc.)
3) Ease of application portability between public and private clouds -- with no vendor-driven requirements within the application stack or control system
Together with OpenStack's Project Havana and Heat, OpenStack Solum will be a direct competitor to other open source cloud PaaSes like Cloud Foundry and OpenShift.