Thanks to an anonymous Story page reader who sent in this link to some old Duality material which I hadn't seen before.
It contains Duality sandbox map shots, map outlines, concept art and models, engine renderings and some textures. A Moorish look was seemingly the order of the day. Sad to see all this work come to nothing.
Most of the Duality stuff on the web is long gone. Here are two links with active content.