I've build an digital clock made out of 144 7 segment displays controlled by an arduino nano. The segments are controlled by 18 MAX7219 ic's which can control up to 64 individual leds or 8 7 segment displays. The array has 144 displays made each up of 8 individual leds so the array has an total off 1152 leds you can control.

(Note: when building this clock make sure the Tiny RTC’s headers are upside down so the battery faces downwards.)