Well, I personally don't think the amount of work that it would take is worth it.
A model that might work though is more of an online article-based periodical, one that is user-submitted but "edited" by the powers that be.
Nothing as fancy as a quarterly PDF but the articles could be made available in that format as well. If users submitted material, and the editor posted that material online (after editing of course, that's what editors do). it wouldn't need to be a quarterly thing, it would be truly periodical as it could wait until there was enough submissions to fill out 2-3 "issues".
Not quite a forum, not exactly a magazine, it's a MAGNUM.