Discrete R2r With Tube Output

The Wells Audio Cypher Dac is fantastic and uses the latest Sabre pro dac chips.

good luck on your search.

@glennewdick 
I just got that LTA Aero Dac and its incredible. Excellent resistor chip and there's no beating a David Berning tube stage of power supply.

Lampizator 

I was just at the hifi show and that LTA aero was in a couple rooms, sounded really good, very smooth and analog.. and it looks really cool

I own the Aqua LaScala that @audiotroy mentioned. It is an outstanding DAC, and while expensive, the modular design insures that any repairs or future upgrades should be cost-effective.