I placed some photos of a rear "Grande Flasque" hub on
http://www.flickr.com/
The surprises I mentioned yesterday had to do with the location of the bend on the flange.
On my front hub, there is space between the spokes and the first row of lightening holes. That is where I bent the flange to give the front flanges their concave shape. (i.e. the bend is on continuous metal, rather than along a radius intersected by lightening holes)
On the rear hub, there isn't much space (at least with the hole pattern I chose). So its very hard to cause the bend to form at a radius not intersected by holes. If you take a good look at original Prior, Maxi-Car, Atom and Airlite Grande Flasque flanges you will see that the bend was made in various locations, often through the holes. You will also see that each company tried many hole patterns.
This leads me to think that such hubs were either made in very small numbers, or home-made.
But without first-hand knowledge, from inside the factories, we may never know.
Amir Avitzur
R"G Israel