I’m starting to work on routines that will support displaying data on multiple 7-segment displays, specifically the 0.56" displays with I2C backpacks, such as these nice green ones sold by Adafruit. I’ll support up to the maximum number (8), limited by the I2C addressing capability of the backpacks. My library will be based on Adafruit’s existing LEDBackpack library, which works great, as far as it goes.
I have three of the nice green displays on order now, and am starting to add the multiple display support to my sketch. So far, it looks like my idea for this support is going to work out fine. As soon as I am satisfied my new display routines work the way they should, I will create a library that will, of course, be BotBoarduino compatible, as a main consideration.
My single display sketch works great, and I will just be expanding this to suport the multiple displays. It also supports one of Adafruit’s large 8x8 matrix displays or small 8x8 matrix displays, which I use to display bit maps that indicate what is being shown on the 7 segment displays.
At some point, my library will also support multiple Adafruit 8x8 (large or small) matrix displays. I think this will be fun to put on robots! 
You could display a robot’s state, current data on motors, sensors, etc, and of course any error indicators. Or, you could just add a bunch of blinkies using the matrix displays. These displays all run very nicely on 3.3V. All my code for these routines, current and under development, is available in my Walter20 repository on GitHub.
8-Dale