Piper Dolls have seamless necks I believe?
I think a Deltan would need to be a tall and slim doll, classic supermodel frame with a supermodel type face (pronounced cheek bones and the like.)
Pipers tend to be cuddly, highly sculpted dolls. And cutesy. Sanhui similarly do many AIO models and cutesy too (slightly less than Piper.)
Pipers also have a soft spot at the back of the head (at least my silicone ones had, not sure if the new ones are like that). The Sanhui don't.
Not sure who else does much seamless neck. EX-Doll does the EXClone range, but they are crazy expensive - $7000.
Never mind, it was an idea. Maybe one day something will turn up. I'm in no desperate rush to buy any more dolls. 🍻