Kitchen Window has carried it in the past so good place to look.
Have you tried my "go to" for odd stuff--Surdyks?
Coops perhaps, or some of the italian grocery stores--Cosettas, Broders and that place in NE i can never remember the name of--Delmonico's Italian Foods. Clancy's had a fennel pollen sausage, so I might try there, too.
Please report back. It is lovely stuff, and I would love to know where you found it.