Haven't the foggiest about how they work, but great things are spoken of the Eastern Electric Minimax and Unison Research kit (actually, not sure if their CD units are solid state...?) but at £900 the EE has to be worth shortlisting if you're thinking of it.
As to how they sound, is it an absolute? I think it depends on the listener - you pays your money and all that. Preferably after a bit of a listen beforehand though. Cetainly, if I had the cash, I'd be shortlisting a good few amps of the valve kind (Icon Audio, Graaf, Unison, Pathos...I'll stop before I get too depressed I think).