Hunter, the video clip didn't work for me. Do you have any suggestions for me? Glad your arm is healing up and keep an eye on the pain. If it gets hot or really really tender or red you might be getting an infected vein from a clot...those can be dangerous so keep an eye on it!
Nicker, I think this is really odd about the seller turning you down, too, but I have a sort of middle-of-the-fence thought about it. First of all, she may know the KMH might not be mentally suited for both disciplines (show & trail), or she may know from personal experience that the horse is difficult to trained for a new discipline. She also may not have a clue about natural horsemanship principles, or may have seen one of the hundred variants of NH that looked like whacking on a horse. So.... we all see things through our own filters and perhaps your positive experiences with NH and 'showing' is very different from the experiences she has had with tightly wrapped show people (or, God forbid, those who show gaited horses in weighted shoes or pads). So, as Koolio said, I don't think this is about you as much as it is probably about what the seller assumes about showing and NH training, etc. or perhaps what she knows about this particular horse's disposition and history.
I have a 15 year old TWH mare who camee to me as a finished trail horse. I made her crazy the first year or so that I had her, trying to do things with her that were different from how she had been trained. Fast forward -- now I have finally realized that the NH training for ME has made me a better horsewoman which has made her an even better trail horse (because she trusts me and we can communicate better), and I've learned a lot more about how she learns, which is very different from my other horses.
So, sorry for the long novel, but I think there might be reasonable explanations for why the seller was cautious. I think they may largely be based on misunderstandings about the broad meaning of NH and how you intend to apply it....and not undersatnding that NH is foundation training, not show training or trail training per se. And, since it appears that she's kept her word to you about looking around for another horse, you have choices as to whether you want to take the next step and see this new horse. At the very least, she knows people who have good horses, right? I would consider whether the lady was as honest as you need her to be, and respectful of you as you need her to be, to continue working with her. As upset as you were, you did still make it sound as if she may have been trying to be both honest and respectful, as well as giving her best opinion as to what these horses (the first one and the new one) could do for you. Trust your gut - you may not be ready to look again yet and that's okay.