One of the best settings for an urban horror game I have ever seen was Dark Conspiracy. Note that I say setting not game because the rules were ehhh. I am not going to go into a review of Dark Conspiracy. Douglas Cole already did it here. Go read it if you want. The man knows his games, bullets and making faux Roman armor for his daughter. Good stuff.
Anyway I was pondering for the umpteenth time how to run DC (Dark Conspiracy, not Douglas Cole though that is a freaky coincidence) and realized I was a schmo because CT would be an excellent game system.
Consider mostly the beasts and monsters in DC are psionic in nature. Traveler has psionic rules You'll have way more special talents and need a few additional powers but those are easy tweaks. One reason I liked Traveller for my Ghost Drive setting. You already have tech levels for different firearms (DC guns can range from TL 6-low TL 9.) You already have rules for claws, fangs and what have you to hang on your monsters. Easy fix.
This got me thinking about other settings you could use Traveller for. First and foremost, World War 2 is crying to be gamed using the vehicle rules (from Striker for you purists). Better yet you can design flying saucers for the Nazi secret weapons or their alien overlords. Not to mention expanding World War 2 out into the Solar system using found or traded for alien tech. What you think the aliens would stop at selling maneuver drives to the Nazis? Nope. Sell to them first and then see what the Americans will pay for it then the Russians etc. Just don't sell the jump drives. The humans be crazy and they might be pissed about their tech monopoly being ruined.
Mixed tech levels like this have been done. Only now they call it retro SF: atomic engines but sliderules to compute courses. Robert A. Heinlein made his name writing such things. For added hilarity have the humans stumble onto jump drive and explode into a peaceful galaxy.
For a final 'new' setting for Traveller imagine a Dark Ages setting where psionic humans are branded witches and struggle for supremacy (or survival) with normal humans. Traveller already has swords, daggers and polearms of various kinds. It could be played as an historical campaign except the witches have real powers and can hit back!