You can't expect contributors to start sending you prints without knowing what direction we're going to take. You may be able to start the ball rolling, but if you don't have some sort of consensus first, how do you expect people to be willing to participate?
When you release a new product, due diligence in market research is required, or you will not know your target audience, what they want, how much they're willing to pay, or if there's even any serious interest. That's pretty much the standard formula if you wish to have some sort of certainty of success; it improve the odds.
I also feel no rush to get this project rolling; it's in its infancy still with the idea having been hatched days ago. What's the rush? Why not calmly compile ideas as they emerge, and then let the people vote. It will be a long thread, yes.