Chris Rose at Eminence contacted me about this project and said that it is underway, full steam ahead. However, this effort has reached a point where it has become somewhat commercial, so I am moving the discussion to the π Speakers forum. Please look for announcements there.
Here is an interesting document written by John Eargle that compares various magnet structures and what performance can be expected from them. A horn provides 10dB to 15dB gain and a similar reduction in distortion. But the geometry of the driver's magnetic flux can do that much or more where distortion is concerned.
Three magnetic structures are compared, each having physical symmetry, but each made with a different material or technology. One is an alnico magnet, the other a ferrite and the third is a ferrite magnet with a flux stabilization ring. So this shows what is gained by incorporating this structure. Each page is a high-resolution scanfile, so if your browser scales them down to a small size, you might right-click and save them to your local computers and print or view them with a paint program or image viewer.