Preamp shootout: Linear tube audio, Modwright, etc.

The two I can think of that could be interesting are:

PS Audio BHK Signature

AVM Evolution PA5.2

In both cases the stock tubes are not optimal.  In the case of the BHK, there is a pair of NOS Tunsgrams that really brings the unit to life and it is a VERY good sounding preamp.  I used it for about a year with a variety of amps and was quite happy.  I scrapped it because PS Audio went direct and I did get a better preamp from Art Audio.  

The AVM uses ECC83s.  I recommend rolling in NOS Mazda Cifte's if you want detail, Mullards if you want sweetness.  This unit is feature packed including tone controls, input attenuation, etc....  I have this unit here now as one of my preamp demos.  

Sorry I missed this guys.  The stock tubes from AVM are good sounding and extremely quiet but are not great in terms of detail and imaging. 
 

Staging is enhanced with good NOS tubes in every direction.  I find depth is most enhanced by Mazdas.  Mazdas are also quite detailed and tonally relatively neutral and flat from a frequency response perspective.

Mullards are slightly rolled off in the treble.  Big staging in every direction and strong levels of detail with a richer midrange.  
 

I have not tried other options.  I have since sold my PA5.2 and those are the only tubes I rolled in.  You could reach out to Tube Depot or Brent Jesse to see what they have to say about their options for ECC83s.