Savvis is about to buy AppFog, a Platform-as-a-Service startup based in Portland, Ore., according to several sources. Savvis, a data center operator itself was acquired two years ago by CenturyLink  (s cl) in a $3.2 billion bid to build a cloud and hosted managed services powerhouse.

logo_savvisDetails are scarce since AppFog had no comment and Savvis could not be reached for comment but sources with knowledge of the deal expect the news to be announced Monday.

Given that Savvis is a big VMware(s vmw) vSphere and vCloud Director partner, AppFog could give it a "house brand" PaaS of its own. AppFog's PaaS builds atop standard Cloud Foundry technology, which came out of VMware. Its pitch was that AppFog abstracted out messy details of base cloud infrastructure so application developers could move their apps from Amazon(s amzn) to Rackspace(s rax) to HP(s hpq) clouds or other public clouds at will. That eliminated cloud lockin at least at the Infrastructure-as-a-Service (IaaS) layer. In April, however, AppFog dropped  support for Rackspace and seemed to be narrowing its focus.

At the time, word was that VMware's decision to spin off Cloud Foundry to Pivotal and offer it as a commercial PaaS hurt members of the ecosystem it had recruited to build PaaSes atop that technology. Those companies include ActiveState, Uhuru and AppFog. There was talk of a possible fork of Cloud Foundry.

Given this news, it looks like AppFog technology will be more tightly wedded to Savvis/VMware infrastructure, but no one's saying.

PaaS as a category hasn't gained a ton of traction in the enterprise -- even some in the market concede that it lacks a killer app to convince CIOs to buy into the concept. Developers at companies often use these platforms hosted on outside cloud infrastructure to build and test software but when the time comes to deploy, the apps typically come in house.

Pivotal trotted out General Electric's $105 million investment in its new venture as proof that enterprise adoption of PaaS is on the upswing.