Bottom line: buy the Raptor. Not the most detailed article but they put the numbers together so you don't have to.
http://www.fordnxt.com/news/buying-a-raptor-vs-building-an-f-150-is-it-worth-it/
http://www.fordnxt.com/news/buying-a-raptor-vs-building-an-f-150-is-it-worth-it/