I am pretty up to speed with poly modelers and am starting to tackle a helmet similar this one, but I thought that this would be cool in Moi or Rhino. Problem is that I am not sure how to start.

I know that it could be approached various ways, but it would be cool if I could get input especially with screen shots and/or steps on how you guys would lay out your curves, surfaces, etc.

I am really only concerned with the main shape and not the vents, cushion, visor, etc..

Any help appreciated!