BTW, Bob Carver's Sunfire amps actually did a pretty simple thing, his "Current" output speaker terminals simply had a 1 ohm resistor in series, to reduce damping factor. In his ads, he stated that the reduced damping factor accounted for 90% of the tube sound. I am not sure how he reached that conclusion...my own opinion is that increased distortion & frequency curve play a role as well.
You are right, one can use standard chips to do many of the things a SET does....including I guess introduce even order distortion. Since I am not an electrical enginner, I will not speculate how one can do that.

-akhilesh

PS: try having a civil discussion liek this in the asylum....ha