Summer Comic Contest (possible?)

I haven't held a contest in ages. (Hope I'm not rusty...)
But anyway, how's this for a contest? I'm thinking of writing a short story, having it illustrated, and then self-published by either lulu.com or blub.com. But this isn't going to be any ol' book... this book will have MULTIPLE artists/writers. That's where you come in!

You, fellow otakus, can create characters and even narrate certain parts of the story. There will be multiple winners because I need a bunch of characters, but the TOP 3 winners will be able to have more than one character in the story. My boyfriend says this idea is kind of like role-playing or DnD. I guess it could be said that it's a role-playing story.
I will come up with an overall plot, create some characters to start things off, illustrate a little of the story, and then the winners of the contest will be able to add their characters to it. Their characters will interact with other characters already create for the story to advance the plot. Each winner will also be able to illustrate their part of the story. And finally when it's all done, me or someone here can make a front and back cover (something simple); and it will be submitted to one of the two self-publishing sites mentioned above to be made into a book. (It'll be like a journal of artists.)

If it all works, I'd like to be able to share the final product with you all by making copies that can be bought. (Winners can have a free copy if it's not too expensive for me to make.)

Now my dilemma is.... how to organize the project. I need help coming up with a simple yet cool plot. I'm thinking of going with the fantasy/action genre. Something like a few ordinary teens living in a dark city (in the slums, subways, tunnels, sewers, etc...) with faeries and goblins and such living there too but in their world called OtherSyde. The teens come into contact with these creatures and get involved in some kind of power struggle or something like that.

CAN YOU HELP ME?! Does this sound interesting to you all, or is it a waste of time?? Please! Any help will be much appreciated. If anyone has ideas for a plot that can be summed up into one or two (at the most) graphic novels, that will be great. I'M OPEN TO ANY/ALL IDEAS!! Thanks.

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