I know nothing about modding an exchange, but I was going to suggest AO3 since it has some infrastructure built in to keep it anonymous and easy to post? Also, I have an invite, if you do go the AO3-route.

What I really wanted to say was that, as long as it's not Christmas-based (or holiday-based or whatever), I can help co-mod or provide any kind of help that you might need because this fandom is just so freaking awesome. So ... just laying it out there. ^_^