Kind of a related update, Yonex have announced an aero road frame with a few photos:
https://cyclist.sanspo.com/409824
The article says they are aiming for a sub-900 g frame weight, with detailed specs to be announced near the end of 2018 and sales start at the beginning of 2019. Article also mentions they've spent time in a wind tunnel designing the frame, frames will be fabricated in Japan and go for somewhere between USD 6-7k.
A disc version of the road frame has also been on sale for a couple of months. Can't find info on the frame weight though.