The contexts furnished by AN 10.60, AN 6.29, MN 119, and MN 36 certainly point to the corporeal body. It is here that we can see the Pali pronoun exhibiting one of its hallmark characteristics - it is functioning anaphorically.
But this context in SN 36.7 does not appear to be corporeal at all -
Tassa ce, bhikkhave, bhikkhuno evaṃ satassa sampajānassa appamattassa ātāpino pahitattassa viharato uppajjati sukhā vedanā, so evaṃ pajānāti: ‘uppannā kho myāyaṃ sukhā vedanā. Sā ca kho paṭicca, no appaṭicca. Kiṃ paṭicca? Imameva kāyaṃ paṭicca.
Bhikkhus, while a bhikkhu dwells thus, mindful and clearly comprehending, diligent, ardent, and resolute, if there arises in him a pleasant feeling, he understands thus: ‘There has arisen in me a pleasant feeling. Now that is dependent, not independent. Dependent on what? Dependent on this very body.
Unless, of course, you wish to suggest that this passage concerns itself only the feelings arisen from the 5 corporeal senses? There does not seem to be any good reason to exclude dukkha arisen from mind contacting dhammas, in which case the kāya here refers to the group of the sense faculties.
In fact, if you look at the next sutta SN 36.8, the same pronoun is applied to refer to “imameva phassaṃ” as the paccaya for such feelings. Given that both suttas are referring to the source of feelings, it seems to me that kāya in SN 36.7 is not the physical body but the saḷāyatana.
And what about this from MN 121 -
Further, Ananda, the monk — not attending to the perception of the dimension of nothingness, not attending to the perception of the dimension of neither perception nor non-perception — attends to the singleness based on the theme-less concentration of awareness. His mind takes pleasure, finds satisfaction, settles, & indulges in its theme-less concentration of awareness.
"He discerns that ‘Whatever disturbances that would exist based on the perception of the dimension of nothingness are not present. Whatever disturbances that would exist based on the perception of the dimension of neither perception nor non-perception, are not present. And there is only this modicum of disturbance: that connected with the six sensory spheres, dependent on this very body with life as its condition.’ He discerns that ‘This mode of perception is empty of the perception of the dimension of nothingness. This mode of perception is empty of the perception of the dimension of neither perception nor non-perception. There is only this non-emptiness: that connected with the six sensory spheres, dependent on this very body (imameva kāyaṃ) with life as its condition.’
It seems very clear that the exercise into Signlessness is a purely mental pursuit, and yet it speaks of “this very body”.
The takeaway from this is that because imameva is functioning anaphorically, the meaning of the noun needs to be teased out from the context of what preceded before. The 2 examples I’ve given should demonstrate that kāya is not always the corporeal body. I would therefore offer that the imameva kāyaṃ in the jhana formulae is referring anaphorically to the previous body mentioned as “his body becomes serene” (kāyo passambhati).
What is the likelihood that this kāya that becomes serene is the corporeal body, when the serenity is the outcome of development of the mind through sense restraint, mindfulness, contentment and abandonment of the hindrances? All of these things work on the mind. If ever there is a time to invoke Occam’s Razor (which should never be allowed anyway), wouldn’t this kāya be referring to your existential heap, ie the conventional “self”?
If you argue as such, then it appears that there are only vehicles for the tenor “body” in the first 3 similes, but that vehicle vanishes and merges with the tenor in the 4th simile. How probable is that?