I don't think Bricasti is the only one. However, their DACs do have their own 1 bit processing for DSD that is proprietary to them and doesn't alter the signal or convert DSD internally in the chip.
I own both the M3 and the M21 and can speak to the general excellence of their DACs. I don't have many native DSD files so I can't speak to the quality of their specific DSD processing. I have upsampled in ROON to DSD, but didn't think there was much improvement over sending direct PCM to the DAC.