TV's are motorized to move back and forth between two points and spin between 2 points. There is a 50' HDMI cable sending video to the TV's. It is routed through a track then down through a pole where the TV mounts.

The existing 50' HDMI cable was provided by the company that provided the motorized track. No brand name on it just "50' " molded into the plug. Today (after working find for a while) HDMI began blanking/snow. At 2 specific points video comes back fine but then it drops off again as it moves beyond those points. My guess is that a conductor is stretched or damaged and at those two points it makes a good enough connection to give me video again.

Video sources/DM Switch/fiber/DM-RMC-100-S and TV have been ruled out as the issue. I can recreate the problem exactly with a test TV and i can eliminate the problem at the existing TV with a new/temporary HDMI cable.

Are there any super flexible/durable HDMI cables out there that can handle the stress of being moved better than other brands?

My other option is to move the crestron DM-RMC-100-S to the TV but i don't know if the fiber i have is any more flexible/durable than the HDMI cable.

What's the bend radius on the pivot points?

I use some specialty cables for robot automation. They are rated at 100,000,000 moves. I can see if any have the capacity for hdbaset, but minimum bend radius would be the starting point.

Fiberoptic would be your other option; again, depending on the bend radius: [Link: gore.com]
Gore's Fiber Optic Core Survives More Than 50 Million Rolling Flex Cycles

I like Planet Waves HDMI for just that reason. Flexible and built well.

Ethereal EHD cables. From .5 meters to 3 meters they are the same size as an iPhone charging cable and they do not get much larger until you break the 10 meter mark. www.ehdcables.com

I have used Vanco and Tributaries small diameter HDMI and none has had a problem, most are on articulating mounts.

While it would be easy to take this opportunity to dump on HDMI, it could have happened in this case with any kind of cable if the routing caused the problem. I NEVER wrap cables tightly to the mount at the pivots, just along the arms. Also, I rotate the cable slightly so it will be relaxed when where it will spend most of its time (if it will be pushed against the wall, or extended the position) to prevent force the twist from damaging it. I also like to prevent the mount from articulating in both directions- this leads to more damage to the cable(s).

Crestron's HDMI cables are actually pretty small and flexible, I would say about the same as the Snap B6 series.