Your right it would be a sequel, but one that I would not be mad in seeing. If it does get made, yes the movie would technically be a sequel but only to us. The movie itself won't be made for another 15 years or so and if and when it does get made I believe we will lose Bill from the title and QT would make a sequel to a movie that takes it's story from a different point of view. What I'm trying to say here is that in 15 years there will be a whole different kind of audience out there. Who knows if we will even be around, my point is that QT has never been fond of sequels but if he does a stand alone movie (Kill Beatrix) it would technically not be a sequel. What if the movie shows Nikki's side of the story, makes her the good guy, trying to find this woman that killed her mother. The movie itself never mentions Bill, or the DiVAS but mainly focuses on this young girls who saw her mother get murdered in front of her eyes. The movie would relate to the audience then and you would not need to have seen Kill Bill, because this movie would stand on it's own. Now I'm not suggesting or really believe this is the right way to go about it, but it does solve that promblem you have about them riding off into the sunset. If this next movie just makes itself look like a stand alone film, where young Nikki must go through B.B. before getting to her enemy Beatrix, we would have another movie with 2 Volumes. Kill Beatrix Volume 1, where we would see Nikki in her journey, and at the films conclusion we would have a face off between B.B. and Nikki. Kill Beatrix Volume 2 would continue Nikki's journey has she makes her way to exact revenge on the Bride. Actually now that I have written all that down, this other direction also sounds pretty bad ass.