There was a company called Bullshark that teased the idea of producing vinyl figures but they never actually released anything.

The difference is that the Japanese factories use a slush casting technique instead of rotocasting or rotomolding. There are plenty of plastic companies in the US that rotomold PVC plastic. The world of designer toys is incredibly small and they probably have no idea what a designer toy is. If they did, they probably wouldn't care enough to market those services because they'd probably still get very little business from it. But if you were to contact them with an example of a platform toy and ask them if they could rotocast a vinyl toy for you, I'm sure many of them could.

I called a place in Pittsburg that does slush casting, about making some toys. They had no clue what I was talking about. Smooth on 60 D is allot like soft vynil. You get those casting lines though.
I would figure the hardest part of that slush casting sofubi process would be obtaining and desposing of those chemicals.
I don't know shit though.
Nothing compare to the stuff made in Japan.

By casting lines, do you mean the seamline from a 2 piece mold?

With the Japanese slush casting, they use the 1 piece metal mold, the vinyl is soft enough after being poured the entire piece can just be pulled from the pour spout.

That Smooth on 60 D does look really soft. Theoretically, and maybe I'm wrong because I am by no means a resin or wax caster. if you didn't make a metal mold, but were using a silicone mold, and you either did your sculpt in wax with your or made a wax casting with the joint pieces in place. You could make a one piece silicone mold, and then just melt out your wax prototype. a slush 60 D cast would probably be soft enough you could just pull it out of the pour spout, without a seamline from a 2 piece mold.