It depends on what you mean by a single piece headstock, cause a single piece headstock is important, at least the way you were lookin' at it in the first mockups. A single piece neck, however, isn't. A scarf joint is stronger than a single piece neck. Here's a good tutorial from perry ormsby about how he does scarfed necks. He uses a jointer but you could certainly do it with a regular hand plane, it would just take a little more time and patience. http://projectguitar.ibforums.com/index.php?showtopic=30212