Honestly what's probably much easier and what is going to happen is Badspot is going to wait for those who are already planning on making trailer's to do so and he'll just use the one he likes. When people like Eksi and Filipe are around to do that sort of thing why would he waste his time making the whole thing himself or making a contest for it? There's no point
Well yes, the chances of Eksi or Filipe's trailer getting used are pretty high. But if there were an actual contest there would be much more incentive for other players to try. As good as Eksi and Filipe are, I know there is potential to be better.
Really, if Badspot plans on using a user-created trailer there is no harm in making a contest. It'd be as easy as telling Rotondo to make an OP with a couple guidelines :P
I'd like to here Badspot or Rot's actual opinion on this idea though. I think it'd be fun
