In my previous Job, a lot of atmel controllers were used for price-signs at petrol stations. Some of those are also used on older Arduino-boards, ATmega1280 and Atmega168.
Ofcourse we didn't use standard Arduino-boards in the final product, just the microcontrollers were used with all other "Price sign"-electronics on the same boards.
Instead of using the Arduino IDE... AVR studio was used (we only got the hex-files by the way), but yes, in theory you can find "Arduinos" everywhere.
We did just the assembly-part, but apparently our client sold the price signs from pole to pole and was one of the biggest. Should you ever need to control 6-16 inch 7 segment displays by arduino and have little problems with ethics..... 