How would it be to have a board attribute "days_old" or "from_date" and "to_date" set by the moderator/admin so that users only see articles in that range, and then can click on a "Archives" link at the bottom that shows rest of the posts for that board. This would be filtering BEFORE the "Number of posts per page" attribute.

This would provide a "time window" on a board, most often from today to certain days in teh past (like a week or a month) and would work great for news item kind of boards!
Shashi