Oracle platform products and architecture have progressed at a rapid pace to meet the demanding needs of SaaS application deployment. We recently (Nov 2012) recorded a webcast on latest capabilites in Oracle Cloud Application Foundation and how we using it as a platform under our own SaaS applications while also offering it as PaaS.
http://www.oracle.com/partners/campaign/eblasts/fusion-middleware-webinar-1842957.html