I think I found them, Revival Signature LED Supernova Brake or Turn-Signal Light - https://revivalcycles.com/products/led-light?variant=258793202&gclid=Cj0KCQjwuaiXBhCCARIsAKZLt3ldhHasUynbdU_SxHvBubc4lmXkyLX_huYRYvSDpYqSOAiRRyLMwzYaAtCxEALw_wcB
And while their web site pics suck, someone has...
I used optronix in my trailer frame. They are really low profile and easy to install.
They come in a bunch of different lens and light configurations, so you can combine brake and reverse with a separate amber turn signal if desired.