DragonflyerThom, allow me to be a busybody for a sec.'
Your posts indicate that you have learned some good-sized chunks of the theory of gyro stability. That already puts you ahead of a lot of bug-stained oldtimers, who don't understand any of it... and who think that booklarnin' is for pantywaists.
But, but, but... there are some gaps. I suggest you study up some more to make sure you can put it all together.
A gyro can be designed so that it does not become pitch-unstable at any speed. In fact, it should be designed that way. If the rotor thrust line gets ahead of the CM at a given airspeed, then the airframe layout is out of whack. The rotor thrust line should swing farther and farther BEHIND the CM as you go faster, because the rotor flies at a flatter and flatter angle. Meanwhile, with proper positioning, design and incidence, the HS will generate more and more nose-up moment as the gyro goes faster. The nose-DOWN moment created by the flat rotor position and the nose-UP moment created by the HS should continue to oppose each other to preserve a nose-level flight stance.
The rotor thrust line may end up on the wrong side of the CM if the gyro has a cabin that creates a nose-down moment too great for the HS to handle. It may also end up there if the gyro has a HTL that the HS can't handle by itself. In either case, the gyro will fly more and more nose-low as the gyro goes faster and faster, and the machine will feel more "twitchy." A machine that remains pitch-stable as it goes faster will feel stiffer and stiffer as you go faster, not twitchier.
VNE in a stable gyro can sometimes be a function of windshields starting to cave in, running out of forward stick (because the flapping angle gets greater as you go faster) or an unacceptable amount of nose-up or left-banking tendency caused by stalling a large amount of the retreating blade.