Hi Vianney and crew,
I would be a nice idea to have a forum where you could upload user created fixture files as attachments to the post.
I know you can configure what type of attachments can be uploaded with phpBB, as I have used and still do use this forum software.
This would enable people to be more pro-active and not have to worry about hosting the file at some other site. It also enables yourselves to get hold of these fixtures modify as needed and include them in the next release of fixture files/DVC etc.