Along with the 747-400 project Boeing also launched a freighter version of it, the Boeing 747-400F. With its maximum payload of about 120t many airlines decided to place an order, or to convert a passenger 744 into a cargo version. It´s largest operators at the moment are for example Atlas Air, China Airlines, Kalitta Air, UPS, Asiana Cargo, Korean Air, Saudia, Cargolux, ABC, SIA Cargo, Cathay pacific Cargo, or EVA Air Cargo. But those are not all. Also some smaller cargo companies, like Martinair Cargo, Etihad Cargo, or National airlines gave their colors to the 747-400F making it their flagship.
Also make sure to check out the wikipedia page, to know more ;)
It would definitely be a great addition to IF, and a must-have for every cargo lover :)