This is a new company located in Prague. Their DAC 8 Stereo should be released soon.
It should integrate a RPI preconfigured with Volumio.
oktoresearch.com/dac8stereo.htm
It is a bit expensive but the measured performances are outstanding:
audiosciencereview.com/foru … -amp.7064/
The PI is connected to the DAC via I2S.
Dominique