Is there anybody interested in seeing a fully balanced dual mono Mainline beside me?
So you want a Mainline that's about twice the price with more noise, higher output impedance, not enough gain, and a higher noise floor?
"Fully Balanced" is a very imprecisely used marketing term by a few manufacturers. We have evaluated plenty of differential and push-pull circuits over the years and we don't plan to offer any. (They actually are simpler and more cost effective to implement in many cases)