Feel free to this but how about one taking place after the Siege of the Crystal Empire arc of the comics. After Sombra and Radiant Hope succeeds in bringing back the Crystal Princess, they return to Equestria where Hope decides to try pair Sombra and Twilight together.

5820675 a excellent story.

5820675 As usual, depends on the execution, but Radiant Hope trying to play matchmaker to Sombra and Twilight sounds like it'd be amusing. Plus, I haven't seen many shipfics of Good Sombra and Twilight...