I remember talking about this over on WotC's forums. Masque of the Jade Dragon was, from what I'm recalling there, a product that was basically meant to be an oriental version of Masque of the Red Death. It was going to be a stand-alone product, and not tie in specifically with MotRD. To the best of my knowledge, however, it wasn't completed or released when White Wolf lost the Ravenloft license.