Sequels to Cowboys & Aliens

Not since Snakes on a Plane have I enjoyed a movie title as much as Cowboys & Aliens.  Waxing (semi) serious for a moment, though, isn't it as likely that aliens would visit the West during the 1800s as it is likely they would visit Devil's Mountain in the 1970s, the plot of plausible sort of movie called Close Encounters of the Third Kind?  Which got me thinking about all kinds of ideas for sequels, should Cowboys and Aliens prove to be a hit.  Here are some of my favorites:

1. Aliens vs. the 300.  Sure, the aliens win in the end, but not before we get to see a lot of alien corpses pile up in the pass of Thermopylae. 
2. Aliens vs. the Gods of Olympus.  Ray guns vs. thunderbolts ... I'd like to see that match-up!
3. Aliens vs. Ninjas.  Speaking of matchups, I'm gonna have to take the ninjas in this one.  What use are high tech weapons against warriors who can move invisibly, shield their body temperature from sensors, and dodge energy pulses?
4. Aliens vs. the Roman Legion.  I'm not sure who would win, but love the idea of the Roman Senate desperately sending forth champions to halt the alien onslaught.  Boy are they going to wish they hadn't turned Russell Crowe into a gladiator.
5. Aliens vs. the Barbarians.  Doesn't matter which barbarians, but am voting for whatever tribe Arnold Schwartzenagger's Conan came from, in hopes all the men are as well developed.
6. Aliens vs. The Knights of the Round Table.  Think about it - this could be a great fit.   Excalibur turns out to be the only weapon that can kill them, and the Holy Grail turns out to be a signaling device that has to be found and destroyed so the aliens can never find us again.  The script practically writes itself!
7. Aliens vs. Nazis.  This is a win-win, because no matter who loses in the end, it's okay with us.
8. Aliens vs. Vampires (or zombies).  Since almost every movie being filmed these days has something to do with vampires or zombies, figure this is a natural.* 
9. Aliens vs. Planet of the Apes.  They've figured out how to outsmart humans, but are the big monkeys ready to outsmart aliens? 
10. Aliens vs. Rednecks. My favorite potential sequel of all, and I'm definitely taking the rednecks.  Can't imagine much more fun than 2hrs of watching aliens get run over by trucks, plowed down by trains, and picked off from behind duck blinds.  And for the finale, the rednecks can lure the aliens to a trailer park just as a tornado is coming ...! ("They never saw it coming, Bubba!" "How could they? We never do!")

(*My son says that Plan 9 From Outer Space has already taken this on, but my recollection is that vampires/zombies are allied with the aliens rather than pitted against them.  Totally different.)