Hi, Guillaume.
I cannot help you, unfortunately, but I have one question. Is there some mailing list here
http://meta.wikimedia.org/wiki/Mailing_lists/overview#Wikimedia_Foundation
aimed to participants of each chapter to share ideas about their local chapters? If not, wouldn't be a good idea to have one? I've read this list, but didn't find what I have in mind...
Also, which IRC channel is better for such kind of discussion #wikimedia or #wikimedia-chapters?
Thanks!
Tom