Create App that always takes up bottom 1/n of screen

I'm thinking about installing the android OS onto custom hardware (Laptop/raspberry pi/other microcontroller to be determined).

I'd like to know if it is possible to create an app/program that would start at launch and always occupy the bottom 1/n-th of the screen (I'm thinking n=3) While the remainder of the screen acts as a traditional android style smartphone.

My hope is to have a touch screen that is divided like:

* [Top portion (n-1)/n of screen] typical android interface doing arbitray tasks

* [Bottom Portion 1/n of screen] remote control for a serial output device and software emulated back, home, volume and [view running apps] buttons.


I'd like to know if something like this is possible and a general way of how I'd go about it.