[@Sierra] I would be very interested in the Yet Another Alien Apocalypse plot.  I would like to know more about the direction that you'd like to go with the world in the RP, and what kind of thin that you'd be going for with the characters, beyond what you have already stated.  After that, I absolutely love to do world-building, so I would be happy to help with that if you want help.

EDIT:  I also really like the concept art for the aliens