Although I don't see the big need for the DAC resistor string to be balanced, balanced signals are most useful for box to box interconnect.... You will get 3 db better S/N ratio, not that it's needed, there should already be 126 db S/N ratio at the resistor string....
This will shave off roughly $500 off the total price of the DAC as well as let me make it a lot less tall than what it is currently, so that's exactly what I did. (9in x 7.5in x 3in or 228.4mm x 190.5mm x 75.4mm).
I added a DB9 port to allow a USB to RS232 cable to be connected in order to enable firmware and filter updates without having to open up the DAC top panel.
Here's the obligatory internal arrangement to show you guys.