Lamm LL1 Signature is a true mono block preamp. completely separate left and right dual chassis. no remote volume control.
https://positive-feedback.com/reviews/hardware-reviews/lamm-ll1-1-signature-dual-mono-preamplifier/
Gryphon Commander likely comes next closest, as it even has two power cords....and a separate power supply connection for the control processes.
https://gryphon-audio.dk/shop/preamplifiers/commander
when you consider the switching and gain functions there is a need for a common control chassis. the Lamm is a bit too ’hair shirt’ for many with no remote volume control. a non-starter for most people.