Volga-Dnepr Group (Airbridge Cargo) just announced their intent to buy another 20 747-8F
Boeing gets cargo boost for 747 jumbo jet at Paris Air Show - MarketWatch
Given the lack of competition and the unique capabilities of the 747 Freighter, my crystal ball says Boeing will be able to keep the 747 line going at ~15-20 aircraft/year for quite a while, building mainly freighters. And if someone comes in and wants a few Intercontinentals, so much the better.