I don't know after sought-after but rare definately a true Amerucana. multicolored, rumpless, blue eggs, weird comb, and feathers sticking out of the side of it's head. Yep, that's definately a looker.
I don't know about the most saught after breed, but if things work out like I am hoping, then I will be receiving a pair of Silver Grey Dorkings in the very near future. I am so excited. I have been reading up on the breed, so that I will be ready for when they arrive.
Many of the hatcheries raise the "rare" breeds. but they pay no attention to the quality of the bird, just the quantity.
So many of the rare breeds are still very rare in superb, preserved heritage or exhibition quality.
That being said, Anconas are pretty rare, I would say the Appenzeller's are rare birds, Dutch bantams in good form are hard to get, I could go on with breeds. The chicken chart is a good source for info.
Real araucanas are pretty hard to find. omg green jungle fowls (not a fun chicken to raise, Id imagine).... large fowl silkies in the US (now there would be something with a market), black fleshed sumatras in the US, OMG Ayan Cemani look that one up on feathersite- thats got to be one of the rarest. Yeah, Im going with cemani.