I had to import the v800 from Europe to get my hands on one and from scouring the internet the v850 is looking pretty scarce. Even FleaBay.the Violectric DACs are excellent, i had an V800, and stepped up to the V850.... According to Fried, theres a considerable difference... then again the V800 is still a damn nice DAC. great performance from a compact unit.
I am thinking of moving up to a V590 V2 which has a DAC in it, but I bet the the v850 is probably more robust than the onboard DAC. I even took a look at Lake People to see if they had a DAC that was similar but seems that they don't like to make separate Dacs anymore.
I guess I'm going to have to wait until somebody is not using their v850 and decides they want to part with it.