I think that it should be possible to distribute clock lines to at least a 16 channel engine using Tayloe polyphase detectors, which have really good noise char

I think that it should be possible to distribute clock lines to at least a 16 channel engine using Tayloe polyphase detectors, which have really good noise characteristics, image rejection, and incredible dynamic range, they also make efficient use of the received signal. One 8 phase clock to feed it all, and coherent downconversion is guaranteed. Parts cost would be $100 or less via Digikey.