These aren't alphanumeric, but they do use 6 LEDs/segments, each digit is about 9" tall, and are driven by TPIC6B595s.
http://www.kiefer.com/kiefer-custom-31--digital-pace-clock-products-2148.php?page_id=160
These aren't alphanumeric, but they do use 6 LEDs/segments, each digit is about 9" tall, and are driven by TPIC6B595s.
http://www.kiefer.com/kiefer-custom-31--digital-pace-clock-products-2148.php?page_id=160