Preamps with separate L/R volume controls

Yeah, the Sachs Model 2 will get u done...

http://www.dsachsconsulting.com/custom%20line%20stage.html

I believe the Atmasphere MP-3 also offers this feature.  Both outstanding preamps!  They don't have physically separate L/R volume controls, but they have separate gain stages for both channels and a master volume control.  Ignore either at your peril. 

There’s a British one....GAH! I forget the name. Black chassis, tubed line stage. Not Ayre.... I can’t remember. I’m fired

The Questyle "Golden Reference System" dual mono setup has separate volume controls for each channel.

Some of the Parasound Halo amps have gain knobs for each channel, as do the pro versions of Bryston amps.

Croft Acoustics!
https://store.acousticsounds.com/d/71374/Croft_Acoustics-Micro_25_Regulated_Preamp-Pre_Amps

@yogiboy that’s it.