It is an interesting design. Not at all new - there have been many DIY projects (some of them are even available on ebay in semi DIY form from Chineese vendors) based on the concept of paralleled 1543 DACs.
What is interesting is that he uses transformers for I/V conversion and no output stage per se (that is why he needs so many of those chips - otherwise he would not have enough current to drive the outputs). Another interesting feture is the use of super regulators throughout, fed from 5 separate transformers.
Even the M2Tech OEM board he uses (this is the M2TOEM-01 model if I'm not mistaken) is fed from the two separate regulators and transformers - he mentioned that he doesn't use USB power, which means that he needs AFAIR +5V and +3.3V supplies to power it.
I'm not a big fan of 1543 chips, as they sound too dark for my tastes. But the whole NOS concept is interesting - I'm a big fan of Metrum Octave DAC myself.