Microsoft has amazing expertise into taking any computer a 3rd party provides and making it work with their software. What about providing "cloud services" that can be guaranteed to never exit your own corporate firewall? I imagine this is going to be a huge need in the near future. I wouldn't be the least bit surprised if it were a standard EU regular within 5 years.
This seems like an amazingly huge opportunity they could capitalize on. Become the standard software cloud solution of all software the way they they own email in the enterprise with exchange. Plenty of companies are large enough to own their own racks of virtualized servers and would pay good money to run well integrated Microsoft software on them.