This is my “Quad Bus Switch Mixer” that I originally published on the Minima transceiver site. It’s designed to take LO input from an Si570 or an Si5351. Preliminary testing indicates very promising performance, with insertion loss about -4.5dB and IP3 at least +30dbm.
I’ll write more about it as time allows:
W3JDR Bright Ideas 
looks very promising! terry