On my '77 Camaro door panels, one thing I like about them is that they can be totally trim shop replicated. Flat "board" for the basic panel. The vinyl and cloth components can be sewn as normal upholstery, and the chrome trim is a part of it, too.
The curve at the top of the panel is a curved piece of ABS that's stapled to the board (top pf the board, bottom of the plastic) appropriately. Not "staple" like from a normal staple gun, but the "trim staples" which are more round in cross section then the "piercing parts" bent over to hold the plastic piece in place. Of course, the plastic is attached before the upholstery is overlaid/glued to the board itself. You don't know the plastic piece is there (which the "cat whiskers" is attached to) until you pull the panel off. The retention of the top of the panel to the inner door body is also a part of the plastic piece, too.
The next project is to determine how to install the retention clips at the bottom of the panel. Might use some Velcro spots rather than metal or plastic clips?
In the section at Home Depot where they have the Masonite and Peg Board 2'x4' plywood sections, the plywood is in various thicknesses, along with the Peg Board/Masonite boards, and some "press board" that's only in one thickness . . . which is about 3x thicker than the OEM "board" for the door trim panels. ANY wood product would need to be fully coated/painted BEFORE it could be used as a door trim panel, for good measure, I believe.
Just some thoughts,
CBODY67