Noktor annouced via Twitter (Click here) that the 50mm f/0.95 for NEX will cost $1.000. The lens will have the same optical design as the current Micro Four Thirds version. Only the look will be different. They are accepting preorders on their website: http://noktor.com/products.php. This is the fastest E-mount lens currently available. If you need a fast lens like that your other alternatives are the Canon 50mm f/0.95 (Click here to see it on eBay) and Leica 50mm f/0.95 (Click here to see ebay auctions). They deliver a better image quality but 1) you need an adapter 2) They are very expensive!
The lens is made by the Hong Kong company SLRmagic which already sells the 35mm f/1.7 for NEX on eBay (Click here).