If I had seen another breed of horse who looked like it could legitimately be carrying the gene I would have no problems saying it was present in other breeds.
I am yet to see a photo of anything other than an Akhal Teke that even comes close to looking like the "satin" gene.
Okay, fair enough. Consider though, that the Silver gene is very loud on some horses, and very subtle on others. Also, notice that the sheen is not as pronounced on rabbits as it is on Akhal Teke - and it is PROVEN in rabbits, although not in the Akhal Teke. Consider that while satin is recessive in rabbits, what we see in horses may not be the same gene entirely, but a similar, incomplete dominant, which would have double the effect when homozygous. Consider that in a breed like the Akhal Teke, where the sheen is endemic, there is likely to be a preponderance of homozygosity ... you can't just rule out every horse that isn't exactly like the Akhal Teke on conjecture. Science demands that ALL the evidence be considered. Not dismissed out of hand. I may not have been able to photograph it adequately - but I am stating, here, that I have a horse that I have seen shining every bit like that Akhal Teke - to the point where traffic was stopping to marvel at it. And that first horse up at the top, with the red glow is definitely not to be dismissed either.
What you do with my observation is entirely up to you.
Thank goodness when people said, "oh, that horse's mane only looks sunbleached to me" we continued, nonetheless to map for silver.