Well, in 1985 there was the Carver challenge, where Bob Carver was able to set up his solid state amp so that the top stereophile editors could not distinguish it from Conrad Johnson's top amp at the time.
He did this by tweaking his amp to duplicate the transfer function of the CJ (at least when a particular set of speakers was in the circuit).
For whatever reason, that seemed to be pretty much the end of it as far as tuning solid state to sound exactly like tubes.
I've never heard of anyone trying to make a tube amp sound more like a particular solid state amp, although there has been a perpetual effort to improve tube amps where solid state has had the edge (bass control, bass/treble extension).
He did this by tweaking his amp to duplicate the transfer function of the CJ (at least when a particular set of speakers was in the circuit).
For whatever reason, that seemed to be pretty much the end of it as far as tuning solid state to sound exactly like tubes.
I've never heard of anyone trying to make a tube amp sound more like a particular solid state amp, although there has been a perpetual effort to improve tube amps where solid state has had the edge (bass control, bass/treble extension).