Maybe it is interessting but we have just modified the moderator new post modification plugin (https://bbpress.org/plugins/topic/moderator-new-post-notification/) a little for the very same reason so we can moderate the first posts of new members. Those are now set to spam automatically and then can be reviewed first. It works together with the Akismet plugin for the moderation naturally.
You can download the modificaiton here (we use 0.9.0.6 so not sure it works with 1.x):
http://www.zenphoto.org/trac/attachment/wiki/ZenphotoPlugins/moderator_notification-moderate_firstposts.zip
Besides, I actually wanted to post this on the plugin’s comments but it seems I can’t.
