Yeah, it's true that other people are doing it a lot. I asked about it on the Linkin Park blog, hopefully someone who knows about it will answer. There has to be some policy, either it's multiple artworks or only one, they just have forgotten to write it down.. I think I'll wait for an answer and then submit more artworks if it's allowed. ^^
I like your works as well.
I really appreciate Linkin Park for giving these kind of opportunities to fans, like with the song remix contest and now this for graphic artists. Also what I appreciate is the way they handle Linkin Park Underground, with all the money the organization makes going back to the organization to make it better. It's so much more than music and that is awesome.