Only problem is that it would have to be fairly heavily moderated...

I like the idea of it being more like a quiz/puzzler.
What about a contest for exp. points. Depending on the level
and some key focus. Maybe even bonus.
The way it sounds right now it does seem like it will need heavy
moderation.

Maybe it could be a priviledge of users of a certain level.
They could have their own discussion or maybe a vote would be beter.
Each user could submit one with their (working) solution.
Then a vote on them. Highest one wins. Points awarded to the winner!
That eliminates <var>some</var> of the moderation <var>(I think)</var>.

So. How about a trial run? I'm not anxious or anything. :)