AFAIK there is only one design of "soft top" door panel - some later ones were grey (i.e. the ones in the German market Defender "cabrio"), but the design is the same.
Earlier 90's and 110's with sliding windows had a multi-piece door panel which consisted of an expanded foam covered with vinyl. A neat-ish design, and possibly better for noise, but didn't have any more space in it.
I think it would be cool to build your own out of sheet stainless, pieces of ABS plastic, and then have the whole thing line-x'd. The shapes are not hard to do. If you study the stock piece, you can see it was basically vaccum-formed over several layers of shaped plywood. Pretty easy woodshop project really.