I wanted to post the head I sculpted in Mudbox 2009 just to show the progression. So here it is.
All posts in 3D
Bowie in 3D
Here is a 3D model of David Bowie that I built in Maya with some Mudbox touch-up. As it turns out police mug shots make great reference for CG modeling because there is usually a clear front and side view. We found our reference pictures at http://www.thesmokinggun.com/archive/years/2007/1108072bowie1.html