Thanks to cujomalainey from the Adafruit Forums for sharing this with us!
Just thought I would put this out there, I made a python package for your Adafruit_RGBmatrix driver that allows users to run off target on their computers so they do not need the hardware to do testing. All it requires is tkinter and pillow.
See the readme for the very tiny changes to the interface. Included is a picture of the nextbus project running in simulator.
Just thought it might be something useful for your customers to develop with.