Hey, good work on that LCD IO Backpack board! So you guys are making workshops around it?
I actually have also an (unpublished) design/prototype for an LCD backpack Arduino-platform based, the main difference being that it was designed to be standalone and provide efficient power to "expansion boards"; it's a bit bigger than the LCD to support a 1A switched buck converter, 3 buttons on the side, a power jack and a simple RS-232 converter - in a single sided PCB you can do at home (4 or 5 jumpers on the component side). I have some ambitious fw and PC sw plans for it, so it's still in the lab, right now being used as an I2C console to debug another project I'm working on!