Some other platforms based on kubernetes supports multiple masters.

For example, Openshift origin support setup cluster with multiple masters and on load balance.

However, Openshift built some customized solutions into kubernetes. Currently k8s couldn't be decoupled from Openshift gracefully.

Personally speaking, I also prefer multiple masters configuration for HA.

There aren't any automated scripts (like kube-up.sh) checked into the Kubernetes github repository that will create an HA cluster; you will need to understand the intricacies of building a cluster (many of which are described in the Creating a Custom Cluster from Scratch guide) and build an HA cluster from scratch or modify a "normal" cluster to make it into an HA configuration.

If you are interested in helping contribute to developing better tools for HA masters, you can join the Kubernetes High Availability special interest group.

kops (https://github.com/kubernetes/kops) is able to provision HA Kubernetes with multiple masters: https://github.com/kubernetes/kops/blob/master/docs/commands.md#other-interesting-modes

AFAIK some more upcoming work is being done in k8s 1.5 and 1.6