Not affiliated, just a happy customer, but anyway: I had good luck building around a DIY low noise class-D design (modulus 86) made by a fellow from Canada, bra

Not affiliated, just a happy customer, but anyway: I had good luck building around a DIY low noise class-D design (modulus 86) made by a fellow from Canada, branding himself as neurochrome audio. It was the first amp I could find that had a low enough noise floor to keep my high efficiency horns from hissing audibly. Mine is a multi-amp setup with active crossover, so I just use these dual monos for the tweeter channels, but they're great. edit: My mistake. When I first read your post I thought you said there were quite few as opposed to quite a few good designs, hence the recommendation.