If you have just a description (and don't mind giving away some of the details) you can post it in Storytellers. If however you have sketches, and a brief description, you can post it in Artists, and if you have models built (simple or not) you can post them in builders.
If you happen to have all three, then you might as well apply for a subforum for the project!
Which I think you would have to contact Kato for that.
