@PaoloM: I need to be able to store large amounts of data, lets take http://soundcloud.com/ for example (or even channel 9 but far smaller scale) where they have a CDN.

The problem is one of storage, as I don't think all the videos here on channel 9 are saved in SQL. NoSQL seems to be the option, but I need load balancing and multitenancy, the ability to process volume shadow copy and so on and pretty good reliability and performance

WCF is pretty powerful in allowing you to get the content onto the server, but I need a clean way of managing it all. I don't need service bus architecture, as at present it will be C++/ or preferably .NET based.