Ultima 7: Blackrock was a project using the Exult engine which aimed to remake The Black Gate and Serpent Isle, adding the long-forgotten Serpent Isle original plot and elaborating on elements in The Black Gate that could have been expanded further.
From their website:
What is Ultima 7: Blackrock?
Ultima 7: Blackrock is a project to addon to and expand the story and game world of the Ultima 7: Black Gate and Ultima 7 Part Two: Serpent Isle games. It elaborates on a lot of "what if" scenarios in both games, adding to an already very open pair of games. It also adds a few new plot elements and twists into the storyline of the two games and brings a lot of elements from previous Ultima games back into the story.