Here you go! Digital Deck Covers makes one. Don't worry that the product picture doesn't look like it, their website is weird that way. I just placed an order with them earlier this month for my FaderPort 8 and my RME Babyface Pro. The FaderPort was in their product list but not the RME, so I entered the dimensions on the custom order page and sent them the link to the product specs, and also told them I wanted the back to be a flap since I leave the XLR connectors plugged in, and the made it for me! I also got covers for my two 13x19 Canon pro printers. I just get the standard black nylon because it looks and feels like really dense canvas, and the inside is coated to not allow dust through. These are not the cheapest covers but they quality is best in class.
