Sigma officially confirmed they will announce a new Full Frame L-mount camera in 2019. The current Foveon tech is really outdated and superslow. A newly published Sigma patent discloses a way to make the sensor readout much faster Instead of the classic three layer sensor Sigma is working on a dual layer layout. Every pixels has a green layer The second layer has an alterning pattern of red and blue sensible pixels.
It wouldn’t be a TRUE Foveon sensor anymore but it would help Sigma to overcome the speed issues