Video Below( Dremata-2013, out of business)  shows two chamber design with top zipper, middle divider, and bottom panel with zipper, or non-skid filler. This could be made with two zippers, or with one top zipper and leaving the bottom of cover open and we could close at our factory.

Video Below shows removable top panel that can be attached to single chamber or to a removable gusset to create a pillowtop. We would sell the single chamber with zipper top panel and then add the gusset if the customer needed to adjust comfort.