Worth mentioning, another strategy for customers is to use an abstraction layer. Good ones include jclouds and libcloud. Still take the point about focus/quality.
Yes this is definitely possible and a multi-vendor approach in the cloud is achievable at quite a low bar in terms of customer size. You only need to look at outages at Reddit and many others to see the benefit of that approach.
Yes, all cloud brokerage attempts have so far stuck to the resources and avoided trying to do any unified billing. Its really tough to accomplish.
Can you think of other areas where competing services have common open billing? Great for sure but difficult commercially. Especially when you start bringing in credit risk and other non-technical factors.
I agree that this is difficult. I wasn't really thinking about competing providers though; more like complementary. Like getting IaaS from one company, CDN from another, DNS from another, etc. One could imagine a federation of pure-play service providers that might be able to compete against the more integrated cloud juggernauts while each company focused on one thing.
