Multi-author question-of-the-day blog — how to?

I’m building a news-driven blog in which invited guest authors will respond to a question of the day (posted by a moderator), and readers will join in the conversation via comments. (Think of the National Journal’s Experts blog or Politico’s The Arena, but with comments threaded in.) Seems simple, but the basic architecture has me stumped.

• The native WordPress approach to this would seem to be a new entire blog for each question, but that’s administratively unsupportable.
• I could make each question a post from the moderator, and then have both guest authors and readers weigh in via comments, using CSS to graphically highlight the author contributions. But then I can’t dynamically build lists and archives of author postings, because they won’t be posts — they’ll be comments.
• Or I could try some variation of the Inline Post or AJAXed WordPress plugins to embed author posts into a “master” post for each question, though that requires constant admin monitoring and page tweaking.

Can anyone point me toward a better way to accomplish this goal? Or if a blog with these capabilities is simply unsuited to WordPress, can you steer me to another blogging tool that won’t cause such deep head-size dents in my cubicle walls? Thanks.

~ Steve McConnell