The hat was just a mudbox cube, smoothed, shaped, pushed and pulled. The only think I moved into Maya for was to duplicate some faces for the hair just to make sure I didn't do anything too destructive to my head model. The sculpted hair was then blended into the head mesh to get rid of the hard lines.
If I was going to take it any further I think I'd have to retopologise it and then start working on the texturing. It's not a workflow I use too often but it's a hell of a lot of fun and sculpting is a pretty relaxing way to spend an afternoon!