This is a company to watch http://www.cohesiveft.com/ – they have two products:
VPN-Cubed provides a virtual network onto the network of a cloud provider. This enables first to keep a standard networking layer which is consistent even if the cloud provided network changes (e.g. IP address changes).
Elastic Server allows real-time assembly and management of software components. This allows the quick creation of easy to use applications which can be easily sent to various cloud services.
However it is the fact that together these services allow virtual machines and cloud services to be moved between cloud IaaS providers without significant real-time work which is important. If their products live up to the promise then users can move to the cheapest cloud provider with ease so driving down costs to commodity supplier levels… and creating the spot market for cloud.