I know I guy who does his own frosting, with some form of viscous paste with hydroflouric acid as the etchant as one of the 'active ingredients'. You clean the glass, rub the paste on, leave it for a period of time that varies depending on how etched you wnat, then rinse it off. All of this is done with rubber gloves and other relevant PPE.
Could the single piece of specialty glass be relaced by two layers, one which deals with the diffusion, and the second one underneath that deals with the heat absorbing?