Does anybody make...

@millercarbon I think has the most practical solution to what you described assuming your pre-amp I assume has low enough output impedance to run essentially 4 passive volume controls. You could use a trim-pot to get the balance right, then some good quality resistors for the final implementation. We are only talking 1/2 watt resistors so cost is minimal.

Oh Oh …… HaaaaaHaaaaaaaa 

This is roughly what you want:

@cakyol @imhififan  

I saw that earlier cakyol, and noted it, looks worth a try, thx