The Meta Cloud concept (my earlier blogpost introducing Meta cloud) has taken a step closer to reality.
Cloudkick (a San Jose based start-up) unveiled an open source project named libcloud, which aims at providing a single programming interface for a host of infrastructure clouds such as Amazon EC2, Rackspace, Slicehost and GoGrid. For example, using libcloud you can make a single API call to potentially reboot your server instances across Amazon EC2, EC2-Europe, Slicehost and Rackspace.
In long run, the plan is to extend these Python based APIs to cover more and more infrastructure clouds such as Linode, Flexiscale and the open source Eucalyptus. If things go as planned, this concept can potentially enable partial interoperability, there by breaking the biggest entry barriers for enterprise adoption of clouds.
For those of you interested in contributing to libcloud project, here is the source code on Github.