Indeed, there is a 50mm f1.1 from Cosina. I did shoot with it in March when we were in japan. Of course, i had to keep quiet about it, which is not easy!
It is a very sweet lens, slightly smaller than an older style Noctilux, 58mm filter thread. Weight seemed to be similar, or slightly lighter. The prototype looked a bit like a Nokton 50f1.5 on steroids. Similar knurling on the focus and it "sat" well in the hand when on the camera. There were two versions of the hood. One was a smallish, thread mount one, slightly flared (minimum intrusion into the finder of the M2 and ZM) and the other one was a larger diameter one with a clamp-on screw.
Image quality was very good. For obvious reasons I shot most everything at f1.1 or there-abouts. The corner fall off is less than on the Noctilux f1.0- looks to be around 1,0-1.5 stops. Less of peering through a tunnel as the Noctilux tended to create. Sharpness at f1.1 is very good - I did not do "resolution" tests - but looking at the negatives - I would have no problem blowing them up to 11x14 or 16x20 without having the lens being the limiting factor. I did shoot most of the pictures with Acros 100 and developed them in Beutler. This is a combination that takes "no prisoners" in terms of sharpness and contrast.
The price seems to be set at around $1100 - but that might depend on exchange rate too.
I will post some shots from it later today.
What I liked is the fact that a/ a bit more compact than the Noctilux and b/ apart from being very good at f1.1 - the quality when stopped down held up and it is nice and sharp throughout the whole f-stop range. This means to me that it could do duty as a "standard" 50mm without loosing image quality in bright light and on the "dark" side.