So, I decided to remove the throttle cable to measure it. That way, I could contemplate a non-PT part...
I started by detaching cable at engine, since it seems the easiest way to remove would be by pulling out from the dash. Once everything was unbolted at the engine, the cable/core was free to be pulled out. I was surprised to find out the cable had broken only 4.5in away from its end...??!! Pretty clean cut; no signs of wear/chaffing/rubbing. A bit surprising/bizarre.
I realized that the cable's routing is longer than it needs to be to reach the engine. Presumably, to avoid engine heat. I thought rerouting cable on a shorter path might give me a temporary solution that might make up the 4.5in that was lost.
I removed 4.5in of sheathing and rerouted the cable; it worked. However, the cable now runs below the oil pan, where it will be exposed to a lot more heat... Time will tell...
I'll still inquire from PT about the cost for a replacement. I also thought of replacing and relocating throttle with a much shorter length that does not run through tunnel. As long as one hand can easily reach a lever from the tractor's seat, the lever does not need to be in the dash... Anyone MacGiver'ed something like that...?