I don't know if this is helpful, but I have a RCA BN5A tube mic pre: must be about 100 dB of gain (more than I've ever seen or used in ANY mic pre), and when the tubes are good, it's pretty quiet, but not in the same league of quiet as modern designs. Look like a brown bread-box, and has 3 tubes (I think they're AX, AT, and AY7's) with the huge bakelite gain knob. Got it years ago from a tube enthusiast, and I've never seen the model of it anywhere else...
Never used any of the others, so I can't comment - anyone ever heard, or seen another of these units?
regards,