I've always found that using an IRC can be infinitely more effective than waiting over the course of days for candidates to post answers. With this model, you can actually get a debate in real-time, and then the moderator would just be tasked with posting a transcript here for everyone afterwards.
Also, in order to not overwhelm the candidates you could have a few debates Worth different themes.
This is an interesting idea. I don't have an IRC account (and frankly don't want one, to be honest), but I'd be fine with someone else moderating.
I do worry that such a format might make it difficult for non-IRC users to hear the candidates positions, though. Perhaps we could have a more traditional debate on the forum over the course of next week plus an additional IRC debate?
An IRC debate can be copied and pasted on to the boards.