Marakanetz, You wrote, "Balanced isn't only 3-pin. It could also be 5-pin stereo-balanced. If the phonostage is fully balanced(recall Violectrik), you can rewire tonearm for 5-pin stereo-balanced transmission." Actually, you would not have to do anything to the tonearm; just bundle the wires for both channels and connect them to one 5-pin connector.
There would be no electrical difference, of course, between using separate 3-pin XLRs, one for each channel, to carry balanced signals, and some sort of 5-pin connector for wires carrying the signals from both channels in one bundle, but I have never seen this done. Have you? Where did you get that idea? And what's a Violectrik? There are many examples of modern true balanced phono stages, but you've stumped me on Violectrik, and I am too lazy to google it. I like the name, though.