Yes, the MSB Reference is the new "DAC VI"
Starting with the Analog DAC, then SELECT II, MSB had a new platform which they built their DACs. and the DAC IV/V series posed serious challenges, as they used an entirely (older) platform. So, when developing the input/output modules that MSB is known for, they basically had to engineer them twice, once for the newer platform (for Analog/SELECT) and then to the DAC V, which used their older platform.
So work began on the "DAC VI", which would employ the new platform, to be common throughout all the DACs. Of course, the "VI" became the "Reference", and the rest is history!
As can be seen on the website, the optional modules on the Reference are pretty much the same as on the SELECT, which makes it easier on the manufacturer and on the customers as well.
That said, we just got a beautiful DAC V yesterday, and I couldn't resist hooking it up for a "refresher". And it's every bit as good as I remember it
The accuracy, the realism, it's still some of the best digital out there, SELECT/Reference notwithstanding!
cheers,
alex