This is another of my "prior art" patent ideas, its something I've talked about before but reading pieces around increasing data volumes its made me think about it more and more.
The big problem with public cloud is that the amount of data that needs to move around is getting exponentially higher. This doesn't mean that public cloud is wrong, it just means that we will need to look more and more about what needs to be moved. At the moment a public cloud solution consists of storage + processing and its the storage that we move around. In that I mean that we ship data to the cloud and back down again. Amazon have recognised the challenge so you can actually physically ship storage to them for large volume pieces, there is however with the continuing rise of Moore's Law and virtualisation another option.
Your organisation has lots of desktops, servers, mobiles and other pieces. The information is created and stored fairly close to these things. The data centre also will contain lots of unused capacity (it always does) so why don't we view it differently? Rather than shipping storage we ship processing? You virtually provision a grid/hadoop/etc infrastructure across your desktop/server/mobile estate as close as possible to the bulk data.
This is when it really gets cloudy as you now move compute to where it can most efficiently process information (Jini folks can now say "told you so") rather than shifting storage to cloud.
The principle here is that the amount of spare capacity in a corporate desktop environment will outstrip that in a public cloud (on a cost/power ratio) and due to its faster network connections to the raw data will be able to more efficiently process the information.
So I predict that in future people will develop technologies that deploy VMs and specific process pieces (I've talked about this with BPEL for years) to the point where it can most efficiently process information.
Public clouds are just new data centre solutions, they don't solve the data movement problem. A truly cloud based processing solution would shift the lightest thing (the processing units) to the data rather than moving the data to the processing units. The spare capacity in desktop and mobile estates could well be the target environment for these virtual clouds.