finding a solid state amp to replace a tube amp

What are the good features of the mv 125 that you want to capture? Not sure what you mean by "treble response".

I've found Pass and Rowland to possess "tube-like" qualities. They still sound like SS though.

I would look first at CJ SS amps, as they are products of the same design team. I use a CJ 350 myself and it is a great amp, although not cheap. But as noted above , tubes and SS have their own sound. If it is to be a back up why not try a different flavor, I am a SS user but occasionally use a tube hybrid pre amp, it gives a different, but equally valid, take on the music.

Don't know about CJ treble response but you might like ARC'z 100.2 and D400MkII amps - both are considered to have some tube like character.