I am experimenting with a DIY horizontal expansion lens (see CAVX's blog--he and I and a few others have been messing around with one).
But it occurs to me that with the ability to rotate these DIY lenses, you are not restricted to just 133% stretch, but can increase it. I have a 4:3 projector that has a full stretch mode (eliminates black bars on 2.35:1 material) and have been able to get my lens to just about get the required stretch needed for constant height.
Unfortunately, I have been limited with time, and haven't been able to continue with the experiments. There is a very long thread running at www.diyaudio.com on this project.
A forum community dedicated to home theater owners and enthusiasts. Come join the discussion about home audio/video, TVs, projectors, screens, receivers, speakers, projects, DIY’s, product reviews, accessories, classifieds, and more!