SuttaCentral
This passage suggests that there is a potential for each of the aggregates (form-ness, feeling-ness, etc.) to turn into discernible aggregates through the process of fabrication.
Is discernment not part of perception? Or process of fabrication occurs before perception?
I read consciousness, feeling & perception occur before fabrication (MN 18, MN 43). 
How do you reconcile the simile of a banana tree with your interpretation?
I think you are onto something. Maybe you want to check into the Chapter on Diversity Nānattavagga SN 14.1-10 . There’s other stuff directly related to what you are thinking about, but it’s not in my mind at the moment as to exactly where … But, I do indeed think you are onto something.
Recently I made a discovery while thinking about how thoughts form. It was a mistake to believe that Form/Perception/Vedana/Conciousness itself as Sankhara. But it is also true that they have the same property as Sankhara.
I think Sankhara is the state before becoming Form/Perception/etc. That’s why Form/Perception/etc still has the property of Sankhara(Layered).
Example:
Before a thought(perception) “I like this car” arises, it arises out of other perceptions/vedana such as “This color is good”, “This shape is cool”, “Nice interior” etc. These countless perceptions/vedana give rise to one thought that is “I like this car”. But before this thought arise those countless perceptions/vedana remained as Sankhara and not become perceptions/vedana. When we examine why I like the car, these Sankhara will become perceptions and give rise to the thought “This is why I like the car”. Until I examine they remain in subconscious as Sankhara.
Sounds like you might have been looking at the Cetanāsutta (SN 12.38). There are a few there in that series that address your thoughts.
Mendicants, what you intend or plan, and what you have underlying tendencies for become a support for the continuation of consciousness. “Yañca, bhikkhave, ceteti yañca pakappeti yañca anuseti, ārammaṇametaṁ hoti viññāṇassa ṭhitiyā.
When this support exists, consciousness becomes established. Ārammaṇe sati patiṭṭhā viññāṇassa hoti.
When consciousness is established and grows, there is rebirth into a new state of existence in the future. Tasmiṁ patiṭṭhite viññāṇe virūḷhe āyatiṁ punabbhavābhinibbatti hoti.
When there is rebirth into a new state of existence in the future, future rebirth, old age, and death come to be, as do sorrow, lamentation, pain, sadness, and distress. Āyatiṁ punabbhavābhinibbattiyā sati āyatiṁ jāti jarāmaraṇaṁ sokaparidevadukkhadomanassupāyāsā sambhavanti.
That is how this entire mass of suffering originates. Evametassa kevalassa dukkhakkhandhassa samudayo hoti …
What you intend or plan/thinks - Sankhara
Conciousness - as a seed
Conciousness grows → New existence
So new existence can be seen as a new thought?
Hi, if you are asking me what the bit of the sutta I gave says, I would say it is saying that intent (which is already formed from some type of mental content) whether active or “latent” shapes a particular receptivity, let’s say attention, to certain things. Roughly speaking, you are now engaged in some type of goal seeking behaviour and marshal to yourself, whatever cognitive and environmental resources you need to get that goal. Once you get it, hey! you are now Prime Minister, next stop god, next stop Buddha, or what have you.
Soteriologically speaking, at any rate, you will be born, and the human condition and mortality will wear on you, painfully, without a doubt.
As far as the full philosophical meaning of sankhara. Probably there are others who can lay out the Theravada interpretation quite well for you. It’s not a pursuit of mine, so I can’t help you with that.
Namo Buddhaya!
Sankhara denote anything constructed as subject to dependent origination.
Kamma is sankhara, kammavipaka is sankhara, intention is sankhara, things willed & intended consciously or otherwise are sankhara. In short the all experienced through the allness of the all and the thought of what is not experienced through the allness of the all are called sankhara.
Only the asankhata is not sankhara.
That’s what I thought at first. But that makes it such that all aggregates are sankhara. A materialist might go the other way and assure that all aggregates are form. A master of deep meditation(perhaps Arupa jhanas) would surely assure that everything is consciousness.