That sounds like a potential Battlefront sequel to me. I don't see why they would make TFU3 on the Unreal engine considering the current engine used is one of the big draws to the game. It would make more sense for it to be BF3.
I'm pretty sure Pandemic owned the rights to the engine used for the first two games, and everything that was used in the third one that never came will never be seen. Using a proven engine like Unreal makes perfect sense to me. Keep your fingers crossed!