Try the Channel Islands D-200s which use UcD modules. These modules take feedback at the speaker terminals and are said to be load independent which would mate particularly well with speakers having large impedance swings. Said to be the best sounding of the class D lot.
Review here:
http://www.positive-feedback.com/Issue22/cia_d200.htm
Review here:
http://www.positive-feedback.com/Issue22/cia_d200.htm