So basically I did a typical vipassana body scan, while simultaneously keeping my awareness open to sounds and the dark visual field behind closed eye lids. About halfway I felt myself dozing off almost as I tried to sustain concentration on body sensations while keeping this peripheral awareness. I suddenly felt pulled back to the sensations of the present moment, and was in a state that I would describe as being "locked into" the present moment. I've recently noticed that body sensations and proprioception in general seems to be the sum of a raw tactile sensation and an imaginary map of the body part in question. The inhale and exhale became one continuous ebb and flow and my body sensations felt increasingly ambiguous as I maintained awareness of my dark visual field on conjunction with the body scan. I felt this pleasant warm sensation throughout my entire body. I wasn't able to maintain this feeling consistently for too long as my hear rate began to increase. I attribute this to the feeling of "excitement" pertaining to the anticipation of entering jhana, in addition to trying to intensify the feeling. I will need to focus on cultivating equanimity during meditation and avoiding distractions. I'm wondering if I what I experienced was anything like jhanic phenomenology, or if I was at least approaching it. 

Yes, a pleasant warm sensation throughout the body sounds like you're starting to tune into piti-sukha, which are jhana factors. Exciting at first, but you'll get used to it No need to force it, just relax and let it spread naturally.
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​​​​​​​That's a good insight. We have this idea that the body is a solid object, but isn't it all just an "imaginary map"?! ...

Same here, I've discovered I have a sort of mental body occupying the exact same space as the physical one and which I refer to when sensations are perceived. Odd, really.

First jhana tends to be very narrowly focused.  Sounds like you were in a concentration state of some kind though, with jhanic factors.