I'm in middle of setting up a masterless kubernetes, which I mean setting up a kubernetes node without setting up kube-apiserver. I was successful defining my Pods in kubelet manifest files, but I wonder is it possible to define services in kubelet manifests too?
I'm sorry, but no -- only pods can be created via manifest files.
Services (along with replication controllers and other API objects) require the orchestration that the master provides in order to function.
If it interests you, you can run the master components on the same node without even needing VMs by using the instructions for a "local" cluster.