In 2014, at the Holy Grail Guitar Show in Berlin, Juha had presented a prototype of this microphone in the Nemo guitar, finally the version released 5 years later. You can check Juha's 2014 interview in this article.
The Nemo guitar with the Valvebucker prototype in 2014:
The Valvebucker in 2019:
Juha Ruokangas interview at Winter NAMM 2019
Until the next interview, keep on playing the guitar!