I think this is the right place...
There is a small otaku shop in my area and I was talking to the owner about Kumoricon (which he has never heard of!!!) and he said he was interested in advertising for you guys with a poster or something. He said to ask you guys if there was something, anything, he could get his hands on that looked nice (More than some rinky dink print out from a printer) he could put on his door to advertise to his customers.
Little news about his shop if interested in how his shop is:
He is the owner, manager, and only employee of a little shop in a bad part of the town with bars on his windows but his shelves stack almost to the ceiling and you can hurt you neck looking at all his stuff. If it exists, he probably has it but that doesn't mean he can always find it in the store or in his storage but if he knows he has it, he'll look until he finds it for you. (He searched for five months once for something one girl wanted. He found it in the end. 
)
He is the ONLY otaku shop in the area and attends the Sci-Fi/Fantasy convention down the street from my house. He's well known around here and a lot of people go to him for anything from comic books to anime/manga to figurines. He has EVERYTHING. Literally. So all of the otaku community around here knows him and he keeps all of us alive. People always trust his judgement and if he recommends something, I've never heard someone say no if they can afford it.
