++ Interesting idea, it seems like this point might have gotten lost in the rest of your message, so I just wanted to highlight it for discussion.

The problems that I see with this would be that 1) It increases the time required for a new post to become front-paged, and 2) It would only work if you were constantly changing the number of votes required to front-page to n+1 (where n is the number of people who front-page articles without actually reading them). You'd need to be constantly changing n as people came or left (or adjusted their front-paging attitudes).