I wonder if "run your own anycast network as a service" would ever make sense as a product. I can't see anyone other than CDN or testing being terribly interested, and a lot of this is included in the raw CDN use case.
There is at least one already out there - http://www.hostvirtual.com/anycast-bgp-cloud/. You have to bring your own IP space (/24 minimum of course). I vaguely remember reading the charges were in the low thousands of dollars per month, but that was a while ago.