I bought a load of MAX7219 8x8 LED Matrices from an eBay electronics components seller I often buy from in China. It's a long delivery time, but they are so cheap and reliable I often stock up on parts for any potential future projects.
These displays are easily controlled by a Raspberry Pi or Arduino and link together really easily to make longer display screens. There are plenty of tutorials and open source libraries for these displays out there so a quick search will get you going.
Due to the size of my printer I have designed this (using SketchUp) for 4 matrices and have linked them together with some connectors (another eBay purhase!), however you can always get the soldering iron out.