I missed to save the auction pictures, but they were quite bad and small as far as I remeber.
To me, it makes sence if CANON experimented with a 35/1.4, like Nikon did. As sensible as the 35/1.5 is for backlite, they did right to slow it down a bit, IMHO. 1/3 f-stop more can have make it worse. As visible with the 50/0.95 CANON high speed lenses had big front elements to catch enough light for the outer picture zones, to be fully usable with color film. Leica had the opposite philosophy which made it a bit easier in lens design, because mad outer light rays just spoil the whole picture, resulting in ghostings and lower contrast. But cutting the outer light rays off results in heavy lite falloff wide open, and this exactly is the behavior of the pre-asph. Summilux.
Just compare the front elements of the Canon 35/1.5 and the Summilux 35/1.4.