Here's something that I cooked up one day, before I realized that I barely have time for picking up CL stunt, much less carrier.
It answers the question "how can I make a balanced handle with a minimum of parts?"
It's shown in the mid-throttle position. There's three moving parts: the up-line arm, with the throttle lever on it, the down-line arm, and the throttle-line link. The up- and down-line arms pivot on the frame, the throttle-line arm pivots on the other two arms.
There will be slight interaction between elevator and throttle, because the throttle link tilts as you pull throttle in or out. I think that there's probably way too little mechanical advantage between the throttle lever and the throttle line movement -- you could extend the down-line arm up instead, but then you may be too insensitive.
So, anyway -- it's a thought, but not fully developed and not even reduced to practice. About the only thing that I'll say that it does do is show a mechanical arrangement that'll give you zero net force on the throttle lever (at mid throttle) given equal line tensions.