This is actually closer to Google-Style operability than it is to Twitter-Style operability. :) Twitter doesn't have an equivalent of GSLB (software load balancer), which is essentially what this is.
Have you seen Google's GSLB? It's not a proxy and it's a rather complex and powerful system. It aggregates and coordinates traffic flow but doesn't directly do any kind of forwarding. You could maybe think of Linkerd like GFE but even still, GFE acts as an edge gateway rather than internal RPC system. This is like a wrapper around stubby or grpc.
I've only ever found two things publicly available on this. The patent related to DNS GSLB http://www.google.com/patents/US7581009 and the video by Simon Newton which describes the global footprint and some of the services https://www.youtube.com/watch?v=DWpBNm6lBU4. Most of what I know about GSLB is from my time working at Google.
Yea, it's a completely different use case. Internally Google has something called Maglev which looks a little more like Seesaw but even still its quite different.
I haven't actually seen anything like GSLB anywhere else. With classic load balancing we've always been taught to proxy traffic through a single point of entry. GSLB flips that on its head and rather provides routing information which clients can then use for the next set of requests. I'm attempting to develop something similar within https://github.com/micro but it's going to be a long time before I even get marginally close to something as powerful as Google has.