Long ago I found an approach to 3D modeling [1] that used a morphable model that was then morphed into the desired shape. Would something like this be possible for voice? A voice model obtained from a gigantic set of samples, that can be manually tuned to sound more masculine/feminine, higher/lower pitched and that can be morphed into the timbre of various samples.

- [1] https://www.youtube.com/watch?v=pSRA8GpWIrA