An ambitious Chinese mod team are currently in the process of creating a Command & Conquer: Generals 2 mod for Zero Hour. It will feature the EU, APA and GLA factions, complete with unit and building models from the cancelled Command & Conquer. It may not be the real thing, but its probably going to the be the closest thing to a Generals sequel that we will see.
You can check out more screenshots and models on their ModDB page.