Can GKE (Google Container Engine) do autoscaling? I know that it allows manual adjustment of node replication, but can it be configured some how to detect load and replicate automatically?
Updating my answer as Kubernetes now has this feature.
Kubernetes now supports horizontal scaling of Pods - http://kubernetes.io/v1.1/docs/user-guide/horizontal-pod-autoscaler.html
If you mean autoscaling of the nodes in GCE rather than the pods running inside it, then yes it can - you can turn on autoscaling for a managed instance group such as GCE - see the docs below but the short version is just edit the instance group to enable autoscaling.