I searched earlier this year and found nothing. A few old sources but none actually still made.
I instead ordered him a custom one from If The Bonnet Fits. https://www.facebook.com/ifthebonnetfits/?fref=ts
https://www.instagram.com/p/BIiawu6B9-U/?taken-by=ohtislove
It was very affordable, for custom…I want to say $40? And the quality is downright gorgeous…much nicer than the expensive Eskadron ones that my tack shop carries. And the turnaround time was a few weeks.
I gave her all the measurements for his unique ears (base, widest, length), as well as what size bridle he wears, and she came back with a perfect fit on the first try. The ear material is stretchy lycra that I think may get a little hotter, but does not bind the way the cheap cotton ears do.