Man this has come a long way. I remember my first Pi I wanted to do this SOO badly. I wound up doing it with a 48w/hr battery and a 7" non-touch automotive backup camera screen. [1]
This was just after the launch of RPi1 and well before Adafruit had all the cool parts that just work out of the box.
I've still got it and I believe it's still got Wheezy on it. Last time I tried she fired up. I've gone through abut 7 Pi's since, but this one will never be re-purposed. This is it's destiny.
The coolest part about it was that the screen, computer, and battery were all modular with velcro and electrical plugs. So the metal case had the regulators and Pi, the black case held the batteries. In under a minute I could remove the screen and Pi from the battery pack and velcro it into all into my car.
This was just after the launch of RPi1 and well before Adafruit had all the cool parts that just work out of the box.
[1] https://www.honestrepair.net/wp-content/uploads/2018/04/Micr...