I just ordered the Viltrox 28mm f4.5 pancake for Sony E mount. Right now, the first 50 people can get it for just $69 on indiegogo. The price later will be $99.
Sonyalpha.blog already reviewed the lens (although took the review down as it was too early to be published). Some guy on sonyalpharumors read it though, and he said the lens had excellent sharpness in the middle of the frame.
https://www.indiegogo.com/projects/viltrox-af-28mm-f4-5-fe-chips-size-ultra-thin-lens#/ 