Old project that did exactly what I would like see done for the esp platform ... but for the Teensy 3.1 ARM development board - https://github.com/10bulls/libmpython
A top secret Seed-Studio project to bring MicroPython & Arduino together
https://github.com/Seeed-Studio/ArduPy
A tiny python-inspired language for embedded computing (Bare-metal)
https://github.com/keith-packard/snek
A lean and efficient Python implementation for microcontrollers (Bare-metal)
https://github.com/micropython/micropython
https://github.com/pfalcon/pycopy
https://github.com/adafruit/circuitpython
Older stuff ...
https://code.google.com/archive/p/python-on-a-chip/
http://www.tinypy.org/
...
* CircuitPython 4.0.0 and later does not support esp8266 boards.