Small bad news: Tokina will not make an A-mount version of their 11-20mm lens.
SAR reader Chris got that official answer when he asked Tokina if they will make an A-mount version of their 11-20mm lens:
We are sorry to inform you that we will not produce AT-X 11-20 mm for SONY mount.
Best regards,
A.T.
Tokina/HOYA div. Kenko Tokina Co., Ltd