It might be easier for you to list the amps you may be considering;then I think you will see responses from people.I would not concentrate on what is high end but more on what mates the best with the speakers you are considering driving.
My shot at answering your question would be;High end solid state; Pass,Roland,gryphon,Plinius,MBL,Spectron,Levision.
Tubes- Atmasphere,VAC,VTL,Manley,Joule Electra,EAR,Cary,Audio Research
These are the amps I consider class A high end there are more I am sure.