The highest state of Samatha that I know exists is the state of Stage III Samatha. This is a state of calm abiding so profound that it is called “synchronization” the way it always feels perfectly delicious. It feels really nice, and the mind does not pursue objects in the sense field. It simply does not make the subject/object distinction to begin with, so the feeling you get is that you’re in “synch” with reality- things seem to be moving right along perfectly according to the most interesting plot of the coolest story ever, because you see the utter perfection of every moment and the utter emptiness of time, body, space, and location. You get a very distinct sense of falling, tumbling, turning, in perfect effortless flow with the universe. This is a state from which a person can finally think in terms of the collective, unswayed by their own personal well-being. The practitioner in this state has attained to Stage 4 of the non-self insight map, and the phenomenon of collective awakening and skillful means becomes the main practice emphasis.
Unification of mind is nearly complete at this stage, and when the meditator sits to meditate, they vibrate naturally with the flow of the universe effortlessly. They have mental and physical pliancy and they can sit for long periods without dullness or distraction. Their mental disposition is a calm cheerful peaceful and energetic state of transcendence. Here they can attain to the deepest levels of meditative insight, as this method works in vipassana into the development of calm-abiding (see dependent origination).
In this stage of samatha, the jhanic background falls away somewhat, and what remains, even without ‘formal practice’ is a transcendent and spectacular. Without attending to the energy in any way, a meditator in stage III samatha will sit down and have the energy of their meditations be consistently very pleasurable and soothing. The meditator is in a state of transcendent unification of mind that feels better than any sensory enjoyment. But the intensity of the joy and pleasure they feel in meditation is dialed down a notch compared to stage II samatha, and a deep, satisfying, pervasive comfort is felt in the body and mind. This is aq state of unsurpassed clarity and mindfulness from which the power of intentions becomes directly clear moment-by moment.