Check this out from Holden in the UK. They look like the stock generators and bolt right up.
http://www.holden.co.uk/displayprod...l&pgName=Dynamos+&agCode=1551&agName=Dynalite
http://www.holden.co.uk/displayprod...l&pgName=Dynamos+&agCode=1551&agName=Dynalite