Tube amp with built in DAC

Peachtree Nova or the older Decco unit. Not exactly what you asked for; they are hybrid integrated amps (SS am, tube output stage on the pre section) but they are inexpensive, sound great (especially the Nova) and have very good integrated DACs.

I bought a Decco for one of my daughters, and I have recently purchased a Nova for my office. Both sound much better than I expected for the price.

Audio Space make the Mini Galaxy, an EL84-based amp with an outboard power supply, a built-in DAC and a small footprint. Output power is 12 watts.

The Glow Amp is one of the best sounding amps for money I have ever heard. Since it is single end there is very little feedback. Just enought to solidify the bass. I am using it with a pair for Silverline SR 11's. They are not the most efficient speakers in the world but more importantly they have a very simple crossover so the impedence curve is nice and steady. I love the el84 power tube. I just picked it up used to see what all the hype was about and I will probably keep it forever.