At ITEXPO, I interviewed with Verio about their cloud services brokerage platform. At first, Verio teamed with Parallels; now, they have their own platform similar to Parallels - and the former VP at Paralllels to help them get their own platform going.
Parallels, shown here at the Hostway booth at Cloud Partners Expo, is a software architecture that was originally a control panel for webhosting companies. It was made more robust and became the control panel for hundreds of SAAS apps. A customer can order a webhosting package, 5 Hosted PBX seats, 5 Exchange seats, a CRM and much more all via the user interface. APIs allow for auto-provisioning and billing.
APS is used by Apptix, Sprint, Hostway and many others as the foundation for a cloud services brokerage. Need some apps? Sign up, pick them, auto-deploy them, bill them.