Voigtlander announced 3 wide-angle lenses for e-mount today! I find them particularly interesting, as equivalents simply do not exist or are troublesome - modern wide lenses strive for speed, older wide lenses have issues on digital sensors. Here are the basic specifications:
• 10 mm F 5,6 Hyper-Wide-Heliar
• 12 mm F 5,6 Ultra-Wide-Heliar
• 15 mm F 4,5 Super-Wide-Heliar
So, the existing 12mm is apparently being redesigned, same as the 15mm was recently - "Voigtländer continues its VM-Mount digital optimization with the new 12 mm F 5,6 Ultra-Wide-Heliar III". However, the really interesting part is the 10mm Heliar, as I am unaware of anything else that wide (I wonder if it is going to be also available in M-mount).
I am confident that these will be great lenses performance-wise, but we will have to wait until early 2016 for the pricing. Meanwhile, here's a link to an excellent review of the redesigned 15mm in M-mount on a Sony a7r. And another one, but with fewer samples.
Now, onto some speculation. Judging by the picture posted on Voigltander's website (if it is a picture of the final designs and if they are to scale relative to each other), the 12mm looks entirely different and will possibly sport a filter thread similar to the redesigned 15mm, i.e. 58mm (or slightly bigger). Same for the 10mm. As for pricing, the redesigned 15mm had a significant price increase over the previous version and the conversion to e-mount will probably add even more. I wouldn't expect any of these lenses to go above 1000US, but they will probably be close, especially the 10mm. If they do go above, then the M-mount versions will make much more sense ( I expect Voigtlander to provide both the 10mm and the 12mm also in M-mount at the time of release).