Last October, when Leica manager Stephan Schulz was badmouthing Sony’s E Mount, and how it simply couldn’t handle faster lenses due to its small stature, Sony come back not long after they said that they could absolutely do f/1.0 lenses. They just don’t think it’s worth the hassle and that the demand simply isn’t there.
Well, they seem to have taken things a little further now. With Nikon’s claim of theoretical f/0.65 lenses, Sony claims that they could produce f/0.63 lenses. And they have diagrams to prove it!