My case is a Zalman Z9 Plus and I was wanting to mod the side panel so that it was mostly acrylic. When I asked how to do that I was told it was best I sent it to a pro to get a better finish. While I was looking around on Zalman's website I saw that they sold "Accessories" one of these being a replacement side panel for the Z9 and Z9 Plus which was largely made up of acrylic. It's called the Z9-TSP but I can't find anywhere to buy it.
If Zalman list it then they must supply it to someone. I would suggest approaching a stockist of their cases and ask if you could purchase one of those fancy windowed case panels through them. You may have to pay up front or put down a deposit but that's about the norm.