HP chief cloud technologist Christian Verstraete contends one size cloud does not fit all. So he explains how CIOs can implement a "managed" or "converged" clouds that looks like a public cloud, but have the security and manageability of a private cloud. In the end, clouds are "managed in a consistent manner." And it's all transparent to end user who can move from cloud to cloud without ever being aware of it.
Converged cloud is a pragmatic approach to cloud computing (Tying disparate, existing approaches together). Many orgs already have public and/or private cloud instances already in progress. Over time you'll want to move between them ... and integrate with traditional IT. While lack of skills may underplay the immediate need, it is a need, nonetheless. Sharing a common stack is one of those things that seems like a goal, an ideal ... but its here today.
(note: I work on projects sponsored by EnterpriseCIOForum.com and HP)