Albert points out how logistically difficult this would be.
It is tough enough to do this with just two products.
I have just attempted such a task to quantify and describe the differences between the Callisto Signature and the CAT Ultimate. This has been over the course of the last two weeks, several hours almost each evening. I did this for both the line stage performance and the phono stage in the CAT comparing to the Callisto's companion Io phono stage. And I repeated my tests several consecutive nights to assure I got the same results. I simply used different music as one starts to go nuts after hearing the same song over and over and over.
With both of these models using a lot of tubes (6922 and 12ax7), there is an endless road of tube combinations to try and get each of these units to perform their "best". And how do we know we ever got to that point?
And then there is the issue that each might work well with a different power cable....or a different IC to the amps. We try to be fair by using the same power cable to each but maybe this is not so fair afterall. And what about complimentary vs. similar characteristics with the rest of the system? How far do we go to get to the point of making a decision that we are satisfied with? Obviously, the more cables we have available to try and the same for tubes, the more opportunity we have to approach the ideal combination but this is a lot of work.
For preamps that use the russian super tube, the logistics becomes easier as we have few if any options. But that removes the chance of tuning the system to one's priorities.
Sooner or later, the only thing to do is to put one in the system and if it gets you attached to the music like nothing else, then declare that as the winner and enjoy your music.