I've been using ZBrush on and off since the 2.x days. It's amazing how the tool has come along over the years.
I thought I'd post a little project I did back in 2010. Although we did'nt manage to get it to the man himself, it's still not a bad little piece.
The Bas Relief was built up 100% in ZBrush, then exported to Artcam for tool path generation and machining.