I've had a chance to use the new Zeiss Touit 12mm for the Sony NEX camera the past few days. I'm loving this lens. Lot's of sharpness, I've very happy with the colours and it's the most useful length... much more useful than I expected it to be.
I also have the new Touit 32mm f1.8, but have been using the 12mm more.
These lenses are for sale at my retail store, www.RangefinderStore.com