Are there passive attenuators that don't zero volume and only offer one input ?

If you want to use LDR's , as I observe in other designs, they find it easy to both achieve silence at zero volume, and to also have as many inputs, as are required.  

True but it's not as pure a signal path. I have owned my LDR passive (Lightspeed) for over 10 years. I have also built/owned other resistor and transformer based passives. The simplicity of the Lightspeed and the ability for it to stay out of the way more so than the other passives is why it is the one that stays in my system.

I'm in agreement with mitch2 - the Khozmo represents exceptional dynamic transparency, and an attractive price.  I use a stereo version, with three inputs and two outputs, Vishay Nude Z-Foils and Takman REX shunts (carbon vs metal film of the REY).  I have two Khozmos, the older one using a stepped attenuator (with Takman REY and the same Vishays), and the newer unit which utilizes relays for volume control.  Both are superb, but I think the relay based unit is the more transparent of the two.  My previous "volume knob" was a set of Intact Audio/Dave Slagle autoformers, via a Shallco stepped selector and a Bent remote control kit.  An excellent unit, which the Khozmos finally displaced.

Here is a balanced attenuator that I just made for someone.....he loves it.

http://tweakaudio.com/EVS-2/custom_modsultimate_attenuators.html

True but it's not as pure a signal path. I have owned my LDR passive (Lightspeed) for over 10 years. I have also built/owned other resistor and transformer based passives. The simplicity of the Lightspeed and the ability for it to stay out of the way more so than the other passives is why
it is the one that stays in my system.

But what I observe is other LDR attenuators, based on what I have learned may be the NSL32SR3 type of LDR, apparently these can offer better audio characteristics, namely lower distortion, the manufacturer Luna Inc stating "best distortion characteristics"  and also as I understand, providing wider resistance range.

Apparently they are also able to easily zero volume with a clever technique, and offer more than one stereo input, as I understand as many inputs that are needed, can be catered for. 

It would  seem then easy enough to solve, not to have  problems like not being able to zero volume, if designs, and designers, have motivation to do so.  The one you mention appearing after so many years,  to lack any motivation whatsoever, to overcome the two said issues.

But what I observe is other LDR attenuators, based on what I have learned may be the NSL32SR3 type of LDR, apparently these can offer better audio characteristics, namely lower distortion, the manufacturer Luna Inc stating "best distortion characteristics" and also as I understand, providing wider resistance range.

This is BS, do your own homework.
The very best is the NSL32SR2S and is the most expensive, second is the NSL32SR2.
The R3 is the cheap one and doesn’t go low enough in volume unless over powered/stressed and won’t last if done so.Cheers George