Have you tried the internet? Took me all of two minutes to find this guy mfratus who has four of them he's working on, and if you follow the links like I did then you will see he's been active as recent as 2 days ago.
https://www.diyaudio.com/forums/solid-state/97124-vsp-labs-trans-mos-amplifier-4.html
https://www.diyaudio.com/forums/solid-state/97124-vsp-labs-trans-mos-amplifier-4.html