There is a brand that specializes in low-powered, Class A amps, many designed for high impedance speakers and single driver systems utilizing Lowther or Fostex drivers. That brand is First Watt (an offshoot of Pass Laboratories).
I heard on such amp in my own system, I believe the F4 model, and it is a terrific sounding solid state amp. You should check out their site:
http://www.firstwatt.com