John Piper started preaching through the book of Romans on April 26, 1998. He finished this past Christmas Eve. It took about 8 and a half years to finish the series. I think it took Lloyd-Jones 13 years. A couple of summers ago, I listened to his sermons on chapters 9-11. Words can't describe the impact these sermons had on me. His last sermon in Romans was a prayer. You can read/listen/watch it here.