Care to share your CI tech stack? Specially the deployment bit automagically updating the balancer. We are internally building that kind of setup at the moment and some insight from experienced people like you would be very helpful. Thanks.
For automatically updating the load-balancer, check out docker-gen (https://github.com/jwilder/docker-gen). I hacked together setup that detects the latest version and points to this-one when a container comes up or goes down. It assumes a lot of things specific to my setup though (versioning of the containers, env vars, ...)