I am a very active member of the "Arduino Brazil" group on Facebook (we are already 13k+ members!!); you guys have no idea on how much is done in that group, and how much I learn from there every day.
One of the members I recently met gave me the idea of making a 4-digit 7-segment "shield" that could be used independently of Arduino (featuring a different form factor). This guy resells in Brazil stuff he buys from Aliexpress, so I assume he knows what he wants (and knows what is available out there).
After a bit of [Google Images] research, I convinced myself that the available shields for that product were virtually inexistent, and decided to give it a try on making my own product.
So what you guys are going to see here is the making of a 4-digit 7-segment LED display using the well-known 74HC595 shift register (for pin saving reasons). My main goal is to sell some of those boards (when ready to it) and make a bit of money. But of course everything will be open-source, since I am not going to reinvent the wheel here.