You might want to call
New World Market
5641 Geary Blvd
San Francisco, CA
They have a lot of dried, smoked, cured fish and meats. I believe they have haddock but not sure its the same as finnan haddie.
Otherwise there is always mail order from the link below.
if you find it i'll be interested too as i have it shipped from scotland or the east coast - haven't had any success finding it in the bay area.
i know you aren't looking for a restaurant that serves it but mention that canteen made a kedgeree yesterday with smoked haddock that was outstanding!