Hi NHdad,
You can see Spindle’s comments here about discontinuing their synthetic latex last May.
While I don’t know of any other synthetic latex options in the area (I don’t keep a record of individual mattresses that each store carries in the many lists throughout the forum) … the better options or possibilities I’m aware of in the Boston area (subject to the guidelines here) are listed in post #2 here.
Dreamfoam also has a three layer synthetic latex mattress here.
Phoenix